Bump strong_migrations from 0.7.7 to 0.7.8 (#16584)

Bumps [strong_migrations](https://github.com/ankane/strong_migrations) from 0.7.7 to 0.7.8.
- [Release notes](https://github.com/ankane/strong_migrations/releases)
- [Changelog](https://github.com/ankane/strong_migrations/blob/master/CHANGELOG.md)
- [Commits](https://github.com/ankane/strong_migrations/compare/v0.7.7...v0.7.8)

---
updated-dependencies:
- dependency-name: strong_migrations
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Gemfile.lock

@@ -594,7 +594,7 @@ GEM
     stackprof (0.2.17)
     statsd-ruby (1.5.0)
     stoplight (2.2.1)
-    strong_migrations (0.7.7)
+    strong_migrations (0.7.8)
       activerecord (>= 5)
     temple (0.8.2)
     terminal-table (3.0.0)