v1.1.1

No functional changes to the library. This release validates the GitHub
Actions release pipeline end-to-end after a fix to the .gem artifact
upload step in 1.1.0's release run.

Changed

• Internal: release workflow now builds the gem locally before attaching
  it to the GitHub Release page; the rubygems/release-gem action does
  not leave the artifact in the working directory after publishing.
• Bumped actions/checkout to v6 in the CI and Release workflows to
  clear the upcoming Node 20 deprecation.