Keep spec website fresh - rebuild periodically

[bact]

• Schedule workflow to rebuild dev spec website periodically, fetching latest changes from both spdx-spec and spdx-3-model repos (develop branches)
  • While PR merges in the spdx-spec repo will trigger the website rebuild, PR merges in spdx-3-model repo will not. This PR will make the dev spec website as fresh as possible towards the push for the new release.
• Will rebuild every 30 minutes during meeting hours (from https://github.com/spdx/meetings/)
• Will rebuild every two hours off meeting hours
• Also add "develop" URL alias to redirect to v3.1-dev (to fix dead link https://spdx.github.io/spdx-spec/develop/ in README) https://github.com/spdx/spdx-spec/blob/265717697f0312058fa90db0fdd74ab32171a6e7/README.md?plain=1#L22-L26

[goneall]

I wonder if there is a way to trigger the build when the model changes. For the LicenseListXML repo, we push commits to the license-list-data repo on merges. We could do something similar where we push some kind of update to the spec repo. It could be as simple as a text file with the last commit hash of the model repo or it could be a complete copy of the markdown files.

[bact]

@goneall That is possible. Need to setup at both side, at the Repo A that will trigger / dispatch the rebuilding signal and at the Repo B that will receive the signal. This way, once changes are made in Repo A, Repo B will be rebuilt.

I never setting that up myself, but looks like a doable thing from here https://www.nieknijland.nl/blog/how-to-trigger-a-github-action-workflow-in-another-repository It probably needs a token for authentication - but there can be other way.