`depcheck` has been updated to the latest version. This version pins
`@babel/parser` to v7.16.4 because of unresolved bugs in v7.16.5 that
result in `depcheck` failing to parse TypeScript files correctly.
We had a Yarn resolution in place to ensure `@babel/parser@7.16.4` was
being used already. That resolution is no longer needed so it has been
removed. This should resove the issue the dev team has been seeing
lately where `yarn` and `yarn-deduplicate` disagree about the state the
lockfile should be in.