Add old non-LTS Node.js versions to engine

Author: ai

package.json

@@ -22,7 +22,7 @@
   "license": "MIT",
   "repository": "postcss/autoprefixer",
   "engines": {
-    "node": "^6 || ^8 || ^10 || ^12 || >=13.7"
+    "node": "^6 || ^7 || ^8 || ^9 || ^10 || ^11 || ^12 || >=13.7"
   },
   "dependencies": {
     "@babel/register": "^7.10.3",