Bump grunt from 1.4.1 to 1.5.2

Bumps [grunt](https://github.com/gruntjs/grunt) from 1.4.1 to 1.5.2.
- [Release notes](https://github.com/gruntjs/grunt/releases)
- [Changelog](https://github.com/gruntjs/grunt/blob/main/CHANGELOG)
- [Commits](gruntjs/grunt@v1.4.1...v1.5.2)

---
updated-dependencies:
- dependency-name: grunt
  dependency-type: direct:development
...

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

package.json

@@ -31,7 +31,7 @@
     "grunt-contrib-jshint": "~3.2.0",
     "grunt-contrib-nodeunit": "~4.0.0",
     "grunt-contrib-watch": "~1.1.0",
-    "grunt": "~1.4.1"
+    "grunt": "~1.5.2"
   },
   "keywords": [
     "dot notation",