Bump grunt from 1.5.3 to 1.6.1 in /searx/static/themes/simple

Bumps [grunt](https://github.com/gruntjs/grunt) from 1.5.3 to 1.6.1.
- [Release notes](https://github.com/gruntjs/grunt/releases)
- [Changelog](https://github.com/gruntjs/grunt/blob/main/CHANGELOG)
- [Commits](https://github.com/gruntjs/grunt/compare/v1.5.3...v1.6.1)

---
updated-dependencies:
- dependency-name: grunt
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

searx/static/themes/simple/package.json

@@ -1,7 +1,7 @@
 {
   "devDependencies": {
     "eslint": "^8.18.0",
-    "grunt": "~1.5.3",
+    "grunt": "~1.6.1",
     "grunt-contrib-copy": "^1.0.0",
     "grunt-contrib-cssmin": "^4.0.0",
     "grunt-contrib-less": "~3.0.0",