Bump apps/mastodon from `68775b6` to `4b7f21a`
Bump apps/mastodon from `68775b6` to `4b7f21a`

Bumps [apps/mastodon](https://github.com/tootsuite/mastodon) from `68775b6` to `4b7f21a`.
- [Release notes](https://github.com/tootsuite/mastodon/releases)
- [Commits](https://github.com/tootsuite/mastodon/compare/68775b60392152d32deda45a261bc1d4f848b44a...4b7f21a28ec59452411b16e66cdbb290d4761b14)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
eliotsykes/real-world-rails