Deprecate @rnx-kit/dep-check

[tido64]

Now that @rnx-kit/align-deps is out the doors, we should deprecate and delete @rnx-kit/dep-check.

• Publish a version of @rnx-kit/dep-check with a message telling people to migrate
• Announce!
  • blogpost on new platform
  • tweet from RN@MSFT account + personals
  • reddit + hackersnews post with link to blogpost
• update upgrade-helper to point to align-deps
  • PR: migrate from dep-check to align-deps react-native-community/upgrade-helper#331
• Monitor download numbers over the next couple of months
  • Mark npm package as deprecated (and tell them to migrate to @rnx-kit/align-deps)
  • chore: remove deprecated dep-check #2097

[tido64]

@rnx-kit/dep-check has now been marked as deprecated. @rnx-kit/align-deps has reached the download numbers that @rnx-kit/dep-check used to have before the rename.