Implement versioned releases

[itrharrison]

We should implement a system for tagging and/or releasing versions of SOLikeT, so it can be more effectively shared and used outside of the active developers.

[timothydmorton]

Looks like mflike is using versioneer? Seems like a reasonable choice for this, too.

[timothydmorton]

@xgarrido looks like this would just involve mimicking this commit here? Is there anything else to it? simonsobs/LAT_MFLike@5cc978a#diff-5d6e227073c5aac49a814bced86874198051ae754d7cd97104082f06156701cc

[xgarrido]

Most of the files and changes done in this commit are automatically generated by versioneer. The way to go is explained here https://github.com/python-versioneer/python-versioneer#quick-install You only have to add a [versioneer] section within setup.cfg then run versioneer install and finally edit the setup.py (versioneer will tell you what to do).

The [bumpversion] in the setup.cfg is not directly related to versioneer (and thus not needed) but we will also use bumpversion to tag release.

[itrharrison]

I have created the v0.1 milestone for this, with the aim of having the code in a good state for versioned release and packaged byt the end of January 2023.