Bump jsbundling-rails from 1.1.2 to 1.2.1 (#298)

Bumps [jsbundling-rails](https://github.com/rails/jsbundling-rails) from 1.1.2 to 1.2.1.
- [Release notes](https://github.com/rails/jsbundling-rails/releases)
- [Commits](rails/jsbundling-rails@v1.1.2...v1.2.1)

---
updated-dependencies:
- dependency-name: jsbundling-rails
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Gemfile.lock

@@ -225,7 +225,7 @@ GEM
       rails-dom-testing (>= 1, < 3)
       railties (>= 4.2.0)
       thor (>= 0.14, < 2.0)
-    jsbundling-rails (1.1.2)
+    jsbundling-rails (1.2.1)
       railties (>= 6.0.0)
     json (2.6.3)
     kaminari (1.2.2)