Internal: Allowed empty input in the stylelint script to avoid errors when no...

Internal: Allowed empty input in the stylelint script to avoid errors when no files are found. Added missing stylelint-config-recommended dependency.

package.json

@@ -76,7 +76,7 @@
   "scripts": {
     "build": "webpack --mode production",
     "lint": "eslint --quiet '**/*.js'",
-    "stylelint": "stylelint --quiet 'theme/**/*.css' 'docs/**/*.css'",
+    "stylelint": "stylelint --quiet --allow-empty-input 'theme/**/*.css' 'docs/**/*.css'",
     "preversion": "npm run build; if [ -n \"$(git status src/ckeditor.js build/ --porcelain)\" ]; then git add -u src/ckeditor.js build/ && git commit -m 'Internal: Build.'; fi"
   },
   "lint-staged": {
@@ -84,7 +84,7 @@
       "eslint --quiet"
     ],
     "**/*.css": [
-      "stylelint --quiet"
+      "stylelint --quiet --allow-empty-input"
     ]
   },
   "eslintIgnore": [