[KED-3043] Add support for Python 3.10

[merelcht]

Description

Add support for Python 3.10

Development notes

Significant things to note:

1. moto had to be updated to a newer version, however when the tests are run in parallel either test_incremental_dataset or test_partioned_dataset would fail intermittently, so I changed the tests to not be run in parallel anymore. This might not be an ideal solution, because it adds run time of about 4 mins to each unit test build. The lower version of moto could still be used for Python versions < 3.10, but the 3.10 build would then still fail if run in parallel.
2. For Python 3.10 matplotlib>=3.5 is needed, which breaks holoviews. I've disabled the holoviews tests for Python 3.10, but also had to ignore that dataset from the test coverage check in pyproject.toml.
3. Pylint gives different results for python versions < 3.10 compared to python 3.10. I've opened an issue on the pylint repo: Issues accessing PurePath.parents by index in Python 3.10 pylint-dev/pylint#5832 My suggestion for now is just mark the lint-3.10 build as not required.

Checklist

• Read the contributing guidelines
• Opened this PR as a 'Draft Pull Request' if it is work-in-progress
• Updated the documentation to reflect the code changes
• Added a description of this change in the RELEASE.md file
• Added tests to cover my changes

[antonymilne]

Nice work!

On the parallelisation of unit tests: I don't really mind the slowdown, but it would be possible to run all of them in parallel apart from 3.10. You'd need to add a when/unless clause into the unit_tests job a bit like we have here (only in main, not develop): https://github.com/kedro-org/kedro/blob/main/.circleci/continue_config.yml#L231-L244

[SajidAlamQB]

Awesome LGTM! 🎉

[lorenabalan]

These were quite handy in making our tests run slightly faster by parallelising. What's the reason for removing it?

[merelcht]

See point 1: #1275 (comment), I could implement Antony's suggestion: #1275 (review)

[lorenabalan]

Apologies, I didn't read carefully enough! I think we should implement some conditions like @AntonyMilneQB suggested or have different moto requirements (whichever is easier). 4 mins is a long time and we were struggling with slow builds before, I'd love it if we could avoid regressing on this. 🙏