This commit enables CI on GitHub Actions. Taken from nilium's repository: https://github.com/nilium/ecks-bops-packages/blob/e9bf829752ab82d1170ceb5da60ad656ef372064/.github/workflows/build.yaml Plus a few changes: - only run CI on PRs - don't run CI on draft PRs or when a PR title or body contains "[ci skip]" - remove some names - use more recent void containers - fix XBPS self update