Release v0.3.0rc2

[stes]

• Make sure all tests pass on the rc branch. Also make sure that the milestone related to this release is fully done. Move issues that wont make it into the release to the next milestone, then close the milestone.
• Head to cebra.__init__ and make sure that the __version__ is set correctly.
• Create a PR between rc and main
• Tag the PR with the release label.
• A github action will be run -- if it doesnt start, try removing and re-adding the release label (step 4).
• Carefully check that the release looks fine --- the version from the PR will be pushed to release-staging and staging in the cebra-internal repo. Note: If you update the PR, these version will not be automatically updated. Repeat step 4 or trigger a manual workflow run if you need to update the staging version
• If all looks good, tests pass and the PR is reviewed, merge the PR using rebase merging.
• Delete the branch
• Checkout the updated main branch, git tag v1.2.3 with the correct format (if alpha/beta tags are used in version, use v1.2.3a4 or v1.2.3b4), and git push v1.2.3 the tag.
• Pushing the tag will update the release in cebra-internal. The source tree will land on main, the pre-build wheel and source distribution on release.

[stes]

Released on test pypi: https://test.pypi.org/project/cebra/0.3.0/

[stes]

GPU tests on datasets pass:

[stes]

Let's potentially wait for one more dataset-related PR from @gonlairo before merging.

[stes]

Waiting for #69

[stes]

Added a docker container for testing --- running full test suite now.

[stes]

All tests pass

cc @MMathisLab for review