message: Patch: run linux build on ubuntu-18.04
  Running on ubuntu-latest means you need a more recent version of glibc which breaks on older ubuntu.
  Thanks to for suggesting the fix.
diff: @@ -20,5 +20,5 @@ jobs:
  (github.event.pull_request.head.repo.full_name != github.repository && github.event_name == 'pull_request_target')
  secrets: inherit
  with:
  - tests_run_on: '["ubuntu-latest","macos-latest","windows-2019"]'
  + tests_run_on: '["ubuntu-18.04","macos-latest","windows-2019"]'
  restrict_custom_actions: false
  