Add GitHub Actions pipeline that triggers a nightly feedstock build

[jdblischak]

This pipeline runs nightly. It updates the recipe to build the latest commit from "main" in the TileDB-SOMA repo, and force pushes to the branch "nightly-build", which triggers the feedstock builds on Azure. Because upload_on_branch: main is set in conda-forge.yml, any binaries produced by this nightly test build are never uploaded to anaconda.org

Other details:

• "-nightly" is appended to the version string. This makes it easier to read the logs, and also ensures that the Python client always builds against the locally built libtiledbsoma
• The pipeline runs every night, but can also be manually triggered in the Actions UI or by editing the workflow file

You can see how this works on my fork:

• nightly-build branch
• nightly actions
• example commit - this gets overwritten each run of the pipeline
• example Azure build logs

Note that the builds are currently failing because the conda recipe uses the flag --libtiledbsoma to build the Python client, and that flag was removed from "main" in PR https://github.com/single-cell-data/TileDB-SOMA/pull/1189

Potential improvements if requested:

• Move the code in the pipeline steps to standalone scripts for easier local troubleshooting
• Automatically open an Issue if the nightly build fails. This is tricky since it requires cross-communication between the Azure builds and a GitHub pipeline (I don't want to directly edit the conda-forge generated Azure files since these will be overwritten by future conda smithy rerenderings). Also this is bound to be noisy since any breaking change will fail until a new release is made
• Fancier version string, eg append the current date

Context: https://github.com/single-cell-data/TileDB-SOMA/issues/1242

[johnkerl]

@jdblischak this is baller!! :)

Re your "Potential improvements if requested" my personal $0.02 is we're OK without all three of these:

• This might be nice ... but as long as we can run-on-demand in GHA, I think that's enough
• A release is a manual, human-decision process with a workflow/checklist & one of those checklist items will be checking this new CI signal. So this is fine. If we ever wanted to move to automated releases (once a month, say) then we should revisit. But I don't see that anywhere on the horizon.
• Nice :)

[johnkerl]

@jdblischak requesting merge-by-requestor rather than merge-by-author; merging