v0.2.2

Maintenance release: no runtime behavior changes.

Infrastructure

• Modernize CI — test Ruby 3.3 & 4.0 against Jekyll 3.x & 4.x, and fix the
  build under rubocop-rspec 3.0 (#30)
• Bump rubocop-rspec to ~> 3.0 (#25)
• Enable Dependabot for GitHub Actions; bump actions/checkout and
  github/codeql-action (#27, #28, #29)
• Add CodeQL analysis workflow

Misc

• Fix a spelling mistake (#24)