Update dependencies & add node/npm version check

package.json

@@ -4,32 +4,38 @@
   "repository": "https://github.com/simplesamlphp/simplesamlphp",
   "author": "olimpiam",
   "license": "MIT",
+  "engines": {
+    "node": ">=10.0.0",
+    "npm": ">=6.0.0"
+  },
   "scripts": {
+    "post-intall": "minimum-node-version",
     "clean": "rm -rf www/assets/css/* && rm -rf www/assets/js/*",
     "build": "webpack -p"
   },
   "dependencies": {
+    "@fortawesome/fontawesome-free": "^5.15.2",
     "clipboard": "^2.0.6",
-    "es6-shim": "^0.35.5",
-    "@fortawesome/fontawesome-free": "^5.14.0",
-    "highlight.js": "^10.4.1",
+    "es6-shim": "^0.35.6",
+    "highlight.js": "^10.5.0",
     "jquery": "^3.5.1",
     "jquery-ui": "^1.12.1",
-    "purecss": "^2.0.3",
+    "minimum-node-version": "^3.0.0",
+    "purecss": "^2.0.5",
     "reset-css": "^5.0.1",
     "selectize": "^0.12.6"
   },
   "devDependencies": {
-    "@babel/core": "^7.11.0",
-    "babel-loader": "^8.1.0",
-    "copy-webpack-plugin": "^6.0.3",
+    "@babel/core": "^7.12.10",
+    "babel-loader": "^8.2.2",
+    "copy-webpack-plugin": "^6.4.1",
     "css-loader": "^3.6.0",
     "expose-loader": "^0.7.5",
-    "mini-css-extract-plugin": "^0.10.0",
+    "mini-css-extract-plugin": "^0.10.1",
     "node-sass": "^4.14.1",
     "sass-loader": "^9.0.3",
-    "style-loader": "^1.0.1",
-    "webpack": "^4.44.1",
+    "style-loader": "^1.3.0",
+    "webpack": "^4.46.0",
     "webpack-cli": "^3.3.12"
   }
 }