Bump spring from 4.1.3 to 4.2.1

Bumps [spring](https://github.com/rails/spring) from 4.1.3 to 4.2.1.
- [Release notes](https://github.com/rails/spring/releases)
- [Changelog](https://github.com/rails/spring/blob/main/CHANGELOG.md)
- [Commits](https://github.com/rails/spring/compare/v4.1.3...v4.2.1)

---
updated-dependencies:
- dependency-name: spring
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Gemfile.lock

@@ -618,7 +618,7 @@ GEM
       version_gem (~> 1.1, >= 1.1.1)
     social-share-button (1.2.4)
       coffee-rails
-    spring (4.1.3)
+    spring (4.2.1)
     sprockets (4.2.1)
       concurrent-ruby (~> 1.0)
       rack (>= 2.2.4, < 4)
@@ -777,7 +777,7 @@ DEPENDENCIES
   simplecov-lcov (~> 0.8.0)
   sitemap_generator (~> 6.3.0)
   social-share-button (~> 1.2.4)
-  spring (~> 4.1.3)
+  spring (~> 4.2.1)
   sprockets (~> 4.2.1)
   sprockets-rails (~> 3.4.2)
   turbolinks (~> 5.2.1)