Prepare release v277

[heroku-linguist]

Commits since the last release:

• Stop bundling bootstrap Ruby (Stop bundling bootstrap Ruby #1481)

For the full diff, see the compare view:
v276...main

[edmorley]

$ bundle exec rake buildpack:release
Attempting to deploy v277, overwrite with RELEASE_VERSION env var
git tag -f v277
git push --tags
Total 0 (delta 0), reused 0 (delta 0), pack-reused 0
To https://github.com/heroku/heroku-buildpack-ruby
 * [new tag]         v277 -> v277
Releasing to heroku: `heroku buildpacks:publish heroku/ruby v277`
Two-factor code: ********************************************
Publishing buildpack heroku/ruby... done
Publishing buildpack was successful