Bump grunt-contrib-concat from 1.0.1 to 2.1.0

Bumps [grunt-contrib-concat](https://github.com/gruntjs/grunt-contrib-concat) from 1.0.1 to 2.1.0.
- [Release notes](https://github.com/gruntjs/grunt-contrib-concat/releases)
- [Changelog](https://github.com/gruntjs/grunt-contrib-concat/blob/main/CHANGELOG)
- [Commits](gruntjs/grunt-contrib-concat@v1.0.1...v2.1.0)

---
updated-dependencies:
- dependency-name: grunt-contrib-concat
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

package-lock.json

@@ -6,7 +6,7 @@
     "grunt-autoprefixer": "~3.0.4",
     "grunt-concurrent": "~3.0.0",
     "grunt-contrib-clean": "~2.0.1",
-    "grunt-contrib-concat": "~1.0.1",
+    "grunt-contrib-concat": "~2.1.0",
     "grunt-contrib-connect": "~3.0.0",
     "grunt-contrib-copy": "~1.0.0",
     "grunt-contrib-cssmin": "~4.0.0",