Bump grunt from 1.3.0 to 1.5.2

Bumps [grunt](https://github.com/gruntjs/grunt) from 1.3.0 to 1.5.2.
- [Release notes](https://github.com/gruntjs/grunt/releases)
- [Changelog](https://github.com/gruntjs/grunt/blob/main/CHANGELOG)
- [Commits](gruntjs/grunt@v1.3.0...v1.5.2)

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

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

Author: dependabot[bot]

package.json

@@ -6,7 +6,7 @@
     "underscore": "1.10.2"
   },
   "devDependencies": {
-    "grunt": "^1.3.0",
+    "grunt": "^1.5.2",
     "grunt-cli": "^1.3.2",
     "grunt-contrib-concat": "1.0.1",
     "grunt-contrib-jshint": "^2.1.0",