Add releasing documentation and/or automation

[gadomski]

It's unclear how this project is released to PyPI. By documenting and/or automating that procedure, the burden is reduced on the maintainer(s) and future maintainer(s) will have an easier time picking up the project.

Examples

• A releasing Github action: https://github.com/stac-utils/pystac-client/blob/37c8181d364fd3341474cca9d74a896b1a49cc0c/.github/workflows/release.yml#L9
• A documented procedure (that includes a Github action): https://github.com/stac-utils/pystac/blob/3be47b283b0e03ee35ca847069022e7456b81ccd/RELEASING.md

[jonhealy1]

This is a really good idea. I have just been running twine manually to push releases. I know there's a process for tagging releases etc. but it's something that I don't fully understand yet.

[jonhealy1]

I will look over the links. Thank you.