git checkout master
git checkout -b image_spec_combined
git mv image/spec/v1.md image/spec/spec.md
# git commit .....

git checkout master
git checkout -b image_spec_1.1
git mv image/spec/v1.1.md image/spec/spec.md
# git commit .....

git checkout master
git checkout -b image_spec_1.2
git mv image/spec/v1.2.md image/spec/spec.md
# git commit .....


# merge the branches (after resolving conflicts)
git checkout image_spec_combined
git merge -S --signoff image_spec_1.1
git merge -S --signoff image_spec_1.2

git log --follow image/spec/spec.md

commit 939675dd24b4c765fce1c4f9286a3ab41880b5a2 (image_spec_1.2)
Author: Sebastiaan van Stijn <[email protected]>
Date:   Wed Aug 30 15:06:25 2023 +0200

    image/spec: rename v1.2.md to spec.md

    In preparation of merging the versioned-specs into a single file,
    with history.
...
...
commit 79910625f0a7aa76590e4362817dda22f28343aa
Author: Josh Hawn <[email protected]>
Date:   Sun Dec 7 23:25:31 2014 -0800

    Adds Docker Image v1 Spec Documention
...