PR sagemath/sage-patchbot#155 adds a GH Actions workflow to sage-patchbot, which runs the patchbot in a Docker container using one of the pre-built images that our CI pushes to https://github.com/orgs/sagemath/packages?repo_name=sage

Follow-ups:

• .github/workflows/run_patchbot.yml: Actually handle github.event.inputs.patchbot_ticket sage-patchbot#156 (fixup)

• .github/workflows/run_patchbot_cygwin.yml: New sage-patchbot#157 (Cygwin)

• Run as a scheduled workflow on GH Actions. Users who fork the GitHub repo can activate the workflow by depositing a repository secret SAGE_PATCHBOT_ENVS of the form ubuntu-focal-standard ubuntu-hirsute-standard .... The workflow would create 1 job per platform listed there

CC: @fchapoton

Component: scripts

Issue created by migration from https://trac.sagemath.org/ticket/33253