Bump grunt from 1.5.2 to 1.5.3

Bumps [grunt](https://github.com/gruntjs/grunt) from 1.5.2 to 1.5.3.
- [Release notes](https://github.com/gruntjs/grunt/releases)
- [Changelog](https://github.com/gruntjs/grunt/blob/main/CHANGELOG)
- [Commits](gruntjs/grunt@v1.5.2...v1.5.3)

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

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

Author: dependabot[bot]

package-lock.json

@@ -4,7 +4,7 @@
     "braces": "^2.3.1",
     "chokidar": "^3.5.3",
     "glob-parent": "^5.1.2",
-    "grunt": "^1.5.2",
+    "grunt": "^1.5.3",
     "grunt-cli": "^1.4.3",
     "grunt-wp-readme-to-markdown": "^2.1.0",
     "node-qunit-phantomjs": "^2.1.1",