feat: Set minimum support Node at 12

Author: nschonni

package.json

@@ -28,7 +28,7 @@
     "url": "git://github.com/sass/node-sass-middleware.git"
   },
   "engines": {
-    "node": ">=8.0.0"
+    "node": ">=12.0.0"
   },
   "dependencies": {
     "node-sass": "^6.0.1"