This is necessary since pronto-stylelint 0.11.0, which we started using
in commit 2768263fa. We were getting an error when runnin Pronto in pull
requests that changed CSS code:
```
bundler: failed to load command: pronto (~/.rbenv/versions/3.2.7/bin/pronto)
~/.rbenv/versions/3.2.7/lib/ruby/3.2.0/open3.rb:222:in `spawn': No such
file or directory - stylelint (Errno::ENOENT)
```