actionlint

actionlint is the original static checker for GitHub Actions workflows, and a good one. It is on Hold because jactionlint started as a fork of it and covers its checks, so a new setup has no reason to pick the original and give up the security rules.

Hold is not a removal order. A repository already running actionlint is not broken. Be careful with package names: actionlint in Homebrew core installs this project, not the fork.