Actualis 0.2.1

Fixed

• The GitHub Action could not load in 0.2.0. GitHub evaluates ${{ ... }}
  expressions anywhere in a run: block, shell comments included, and the
  comment explaining 0.2.0's own fix contained an empty one. Every caller got
  "An expression was expected". The CLI was not affected. A new test fails the
  build on any empty or unclosed expression in action.yml or a workflow, so
  this is now caught before a release instead of by the post-release
  self-test.