Add RELEASE.md or equivalent docs

[consideRatio]

I'd like to be able to learn about the release procedure, and figure it should be documented in the repo. Ideas on what it can include are...

• High level summary
  • We currently do/don't maintain a changelog like...
  • We currently push a date associated tag like v-2025-09-17-1809 and them trigger a version build?
• Practical end-to-end procedure of making a release

For reference, here is a template RELEASE.md for new jupyterhub projects, and associated template github workflow to release a Python package to PyPI.

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background from Tilo: the release process involves signing artifacts so they can work well on windows machines, which makes the release process less straightforward.

There is documentation at https://gitlab.com/sensmetry/internal2/tech/syside/sysand/sysand-signing in its readme about this!

Loose notes

• The GitHub environment pypi-publish requires a manual approval, currently by either Vytautas/Victor/Tilo
• Maven Central has a manual "Go live" button that we need to press following an upload, practically by visiting https://central.sonatype.com/publishing with access to Sensmetry org there, currently Simonas/Vytautas/Tilo have that.

[andrius-puksta-sensmetry]

We currently push a date associated tag like v-2025-09-17-1809 and them trigger a version build?

Date-associated tags will go away (we plan to have a single rolling nightly). Release is somewhat convoluted since we use our GitLab to sign the release binaries.

[andrius-puksta-sensmetry]

We currently do/don't maintain a changelog like...

Changelog is planned. Probably the best option would be to include the same stuff there that we put into release notes. Automatic generation was considered, but it would be simultaneously noisy and incomplete.