Fix versioning

[michalk8]

Implements #94

[michalk8]

@Marius1311 - I think we will be able to put this on PyPI soon. However I'd like these to be merge before an official release:

• Further speed up CFLARE by providing initial guess for gmres #222 (Marius) - is this straightforward?
• Introduce symmetric normalization for transition matrices #219 (Marius) - I think this can be done pretty fast
• Scanpy 1.5 compatibility #141 (Michal) - I suggest requiring scanpy>=1.5 (scvelo does it as well) and save the transition matrix in .obsp
• Automating the coverage update #192 (Michal) - the problem seems to be with the bashuploader - I've changed the workflow, not using the codecov-actions, but only the uploader, and it still doesn't work (because the uploader detects whether we're in an Action or not) - I suggest doing it manually for now, until someone responds on codecov-actions with a solution.
• Add new installation instructions (Michal) - also for development
• Add release notes
• Create PyPI and optionally Bioconda package

Also we should start documenting the releases in our docs.

[michalk8]

@Marius1311 Can you try downloading from PyPI test?
pip install -i https://test.pypi.org/simple/ cellrank==1.2.1a0

[Marius1311]

Thanks Mike! #222 is done. #219 mainly aims at our transition matrix to be the same as scanpy's in case we only use a ConnectivityKernel. I will open a PR for this with an associated test that makes this more obvious. I should be able to do this later today or tomorrow.

[Marius1311]

Re #141, fine by me to require scanpy>=1.5. Feel free to make the required changes and to close #144

[Marius1311]

Re #192, maybe Phil can help? manual would be fine with me for now as well.

[Marius1311]

Okay, running pip install -i https://test.pypi.org/simple/ cellrank==1.2.1a0 gives me

ERROR: Could not find a version that satisfies the requirement matplotlib>=3.0.3 (from cellrank==1.2.1a0) (from versions: 2.2.3)
ERROR: No matching distribution found for matplotlib>=3.0.3 (from cellrank==1.2.1a0)

[Marius1311]

I'm running python 3.6 in a new conda environment if that helps.

[Marius1311]

#219 is not super relevant at the moment, we can safely do this after pypi release.

[michalk8]

Ok, let's do it as follows: I will fix #141 and post in on PyPI as pre-release (i.e. v1.0.0-alpha or similar). Once the manuscript is done (and other issues are fixed), we'll bump the version.

[Marius1311]

sounds good to me.