Update dependency netlify-cms-app to ^2.15.53

Author: renovate-bot

package.json

@@ -45,7 +45,7 @@
     "hugo-bin": "^0.76.0",
     "imports-loader": "^0.8.0",
     "mini-css-extract-plugin": "^0.12.0",
-    "netlify-cms-app": "^2.15.27",
+    "netlify-cms-app": "^2.15.53",
     "node-sass": "^4.10.0",
     "npm-run-all": "^4.1.5",
     "optimize-css-assets-webpack-plugin": "^5.0.1",