Restore the Ruby 2.6-3.1 test checks - #902

Merge pin-ci-runner-to-ubuntu-24.04 (sds#902) so the rspec
checks for Ruby 2.6 through 3.1 run on ubuntu-24.04, where setup-ruby
still has those versions. This merge drops out once sds#902 lands
upstream.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01Wo4FerFK9aaxrGrmVE9ncZ

Merge pin-ci-runner-to-ubuntu-24.04 (sds#902) so the rspec
checks for Ruby 2.6 through 3.1 run on ubuntu-24.04, where setup-ruby
still has those versions. This merge drops out once sds#902 lands
upstream.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01Wo4FerFK9aaxrGrmVE9ncZ

Use the same approach as sds/overcommit#902:
- Add runner as a matrix variable defaulting to ubuntu-26.04
- Use include to override runner for Ruby 3.0, 3.1, 3.2 to ubuntu-24.04
- Pin finish job to ubuntu-26.04

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

* origin/main: (108 commits)
  Remember all previously approved configurations and hooks (sds#665)
  Keep deleted and renamed paths absent while stashing changes (sds#928)
  Document the case-sensitive KtLint hook name (sds#927)
  Update CI actions and pin Ubuntu to clear annotations (sds#926)
  Preserve standard input bytes when forwarding hooks (sds#925)
  Preserve Git-quoted filenames when running all hooks (sds#924)
  Fail when Git cannot enumerate tracked files (sds#923)
  Add note about disabling default hooks (sds#922)
  Close files inspected by LineEndings (sds#921)
  Use Script Host before PowerShell for Windows parent query fallback (sds#920)
  Cache Windows dependency resolution with daily refreshes (sds#919)
  Avoid PowerShell startup for Windows parent command queries (sds#918)
  Avoid repeated CLI startup when preparing integration fixtures (sds#917)
  Allocate more CI runners to Windows with asymmetric sharding (sds#916)
  Shard CI tests across runners and add one required CI check (sds#915)
  Remove EOL Ruby versions from the CI matrix (sds#914)
  Cut CI test time by 68% while preserving the full test matrix (sds#913)
  Cut version 0.75.0 (sds#912)
  Re-enable the full Windows test matrix and fix platform failures (sds#911)
  Read .overcommit.yml as UTF-8 in the hook template (sds#910)
  Update Overcommit logo (sds#907)
  Cut version 0.74.0 (sds#906)
  Keep each worktree's signatures separate (sds#903)
  Recognize amend aliases on macOS (sds#904)
  Exclude files deleted from the working tree from all_files (sds#905)
  Restore the Ruby 2.6-3.1 test checks (sds#902)
  Delete subprocess output tempfiles once they are read (sds#901)
  Stop wrapping commands in cmd.exe on Windows (sds#898)
  Allow URL-only lines to exceed TextWidth body limit (sds#900)
  Cut version 0.73.0 (sds#896)
  Add automated release flow (sds#895)
  Instruct oxfmt not to fail if no files are matched (sds#894)
  Add filetypes to oxc tools (sds#893)
  Add pre commit hook for herb-lint (sds#892)
  Cut version 0.72.0 (sds#891)
  Remove maintainability badge (sds#890)
  Require patched REXML version (sds#889)
  Fix operation state restoration in linked worktrees (sds#887)
  Fail Flay hook when flay crashes instead of silently passing (sds#885)
  Fix Solargraph regexp capture warning (sds#886)
  Cut version 0.71.0 (sds#883)
  Prepare for the new solargraph typecheck format (sds#873)
  Make hook context input reads thread-safe (sds#882)
  Cut version 0.70.0 (sds#880)
  Add oxc pre-commit hooks (sds#879)
  Add Ruby 3.4 and 4.0 to CI matrix (sds#878)
  Cut version 0.69.0 (sds#877)
  Use Etc.nprocessors and handle sandboxed environments (sds#876)
  Cut version 0.68.0 (sds#872)
  Add solargraph pre-commit hook for typechecking (sds#871)
  Update RuboCop in Gemfile to silence a deprecation warning in build (sds#870)
  Cut version 0.67.1
  adds 'set' requirements to diff hook context. (sds#866)
  Add note about unsupported YAML features in `gemfile:` line in default.yml (sds#865)
  Cut version 0.67.0 (sds#864)
  Restore ability to specify "gemfile: false" in config (sds#863)
  Cut version 0.66.0 (sds#861)
  Add `-diff` cli option for running precommit hooks against diffs (sds#860)
  Cut version 0.65.0
  Load bundled gems on expected version (sds#859)
  Update changelog
  Bump rexml to >= 3.3.9 to resolve GHSA-2rxp-v6pw-ch6m (sds#857)
  Expand tildes(~) for hooksPath (sds#853)
  Fix spec compatibility with recent git versions (sds#854)
  Update changelog
  Cut version 0.64.0 (sds#852)
  Add changelog_uri to gemspec (sds#851)
  Support stylelint 16+, which emits messages on stderr (sds#848)
  Add Ruby 3.3 to CI matrix (sds#849)
  Update README with latest requirements (sds#845)
  Fix README badges (sds#844)
  Cut version 0.63.0 (sds#843)
  Add RSpec Hook to PreCommit, Add Applicable files if set (sds#842)
  Fix RuboCop warnings (sds#841)
  [FEATURE] New pre-commit hook: Sorbet (Issue sds#825) (sds#826)
  Green CI PoC (sds#833)
  Revert "Get suite running smoothly again (sds#824)" (sds#840)
  Get suite running smoothly again (sds#824)
  Cut version 0.62.0 (sds#821)
  Allow childprocess 5 (sds#820)
  Update branch for CI from `master` to `main` (sds#819)
  Update RuboCop (sds#818)
  Adding Ruby 3.2 to test matrix (sds#816)
  Cut version 0.61.0 (sds#817)
  fix: local overcommit file merges with existing .overcommit.yml file (sds#815)
  Allow ReplaceBranch to use skip_if (sds#809)
  Cut version 0.60.0 (sds#807)
  Add non ASCII encoding schema support to RailsSchemaUpToDate hook (sds#786)
  Rescue Psych::DisallowedClass in YamlSyntax (sds#805)
  Add optional additional local configuration (sds#799)
  Add MixTest hook (sds#802)
  Add MixFormat hook (sds#801)
  support trailing space in replace_branch's 'replacement_text' config (sds#804)
  Allow overriding Gemfile.lock (sds#796)
  Cut version 0.59.1 (sds#785)
  Revert addition of `--disable-pending-cops` flag to RuboCop (sds#783)
  Revert `Fix encoding of process output under windows` (sds#784)
  Cut version 0.59.0 (sds#780)
  Partial log flushing to make long hooks intuitive (sds#777)
  Fix pronto hooks swallowing generic errors (sds#779)
  ...

# Conflicts:
#	CHANGELOG.md
#	README.md