Sometimes it is convenient to run the Github workflows on a branch other than the main/develop one. Currently, one needs to open a PR on github for this. With the changes in this ticket, one can simply run the workflow directly from the sagetrac mirror on the desired branch.

Documentation: https://docs.github.com/en/free-pro-team@latest/actions/reference/events-that-trigger-workflows#workflow_dispatch

CC: @mkoeppe

Component: build

Author: Tobias Diez

Branch/Commit: 70ca199

Reviewer: Matthias Koeppe

Issue created by migration from https://trac.sagemath.org/ticket/31210