Use Rubygems Trusted Publishers to publish

[ydah]

Follow up:

• Use Rubygems Trusted Publishers to publish rubocop-rspec#1829
• Automatically create release notes rubocop-rspec#1859
• Publishing: Only push antora.yml if it's changed rubocop-rspec#1864
• Improve release workflow rubocop-rspec#1869

Note that this requires the following settings to be checked on:

---

Before submitting the PR make sure the following are checked:

• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• [-] Added tests.
• [-] Updated documentation.
• [-] Added an entry to the CHANGELOG.md if the new code introduces user-observable changes.
• The build (bundle exec rake) passes (be sure to run this locally, since it may produce updated documentation that you will need to commit).