Bump importmap-rails from 2.0.3 to 2.1.0 (#1298)

Bumps [importmap-rails](https://github.com/rails/importmap-rails) from 2.0.3 to 2.1.0.
- [Release notes](https://github.com/rails/importmap-rails/releases)
- [Commits](rails/importmap-rails@v2.0.3...v2.1.0)

---
updated-dependencies:
- dependency-name: importmap-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

@@ -272,7 +272,7 @@ GEM
     http_parser.rb (0.8.0)
     i18n (1.14.6)
       concurrent-ruby (~> 1.0)
-    importmap-rails (2.0.3)
+    importmap-rails (2.1.0)
       actionpack (>= 6.0.0)
       activesupport (>= 6.0.0)
       railties (>= 6.0.0)