These are required by some docutils translators

updates:
- git://github.com/pre-commit/pre-commit-hooks: v3.4.0 → v4.0.1
- https://github.com/timothycrosley/isort → https://github.com/PyCQA/isort
- [github.com/PyCQA/isort: 5.8.0 → 5.9.3](PyCQA/isort@5.8.0...5.9.3)
- [github.com/psf/black: 20.8b1 → 21.7b0](psf/black@20.8b1...21.7b0)
- https://gitlab.com/pycqa/flake8 → https://github.com/PyCQA/flake8
- [github.com/PyCQA/flake8: 3.9.1 → 3.9.2](PyCQA/flake8@3.9.1...3.9.2)
- [github.com/pre-commit/mirrors-mypy: v0.812 → v0.910](pre-commit/mirrors-mypy@v0.812...v0.910)

Co-authored-by: Chris Sewell <[email protected]>

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

See https://github.com/executablebooks/markdown-it-py/releases/tag/v2.0.0,
and https://github.com/executablebooks/mdit-py-plugins/releases/tag/v0.3.0

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Chris Sewell <[email protected]>

Change cell alignment classes to `text-left`, `text-center`, or `text-right`,
and allow tables with no body.

This allows for converters like `optional_int` to work correctly

Field lists are mappings from field names to field bodies, based on the
[reStructureText syntax](https://docutils.sourceforge.io/docs/ref/rst/restructuredtext.html#field-lists).

A prominent use case of field lists is for use in API docstrings,
as used in [Sphinx's docstring renderers](https://www.sphinx-doc.org/en/master/usage/restructuredtext/domains.html#the-python-domain).
This should hopefully pave the way for use with `sphinx.ext.autodoc`

This commit updates the docutils only `Parser`, to include relevant MyST configuration options,
which can be used with the docutils API, CLI or via a `docutils.conf` file.

CLI commands are also exposed for docutils writers:
`myst-docutils-html`, `myst-docutils-html5`, `myst-docutils-latex`, `myst-docutils-pseudoxml`, `myst-docutils-xml`.

In addition,
the commit also stops mathjax classes being added to sections, when parsing in docutils mode,
and adds help metadata to the `MdParserConfig`attributes (for programmatic documentation).

Co-authored-by: Chris Sewell <[email protected]>

This commit adds a workflow for releasing an additional package `myst-docutils`,
which does not include install requirements on docutils or sphinx.
This will allow the docutils package to utilise it as a dependency, with no cyclic dependencies.

The package is created by dynamically modifying the `setup.cfg` and `README.md` before the build.

The build is also tested against a range of docutils versions,
to ensure it does not fail due to the missing sphinx dependency.

The change allows compatibility with the
`sphinx.ext.autodoc.directive.DummyOptionSpec` instances.

This commit adds more tests related to language translations.