Remove plugin config for auto-install

Author: verythorough

netlify.toml

@@ -1,6 +1,3 @@
 [build]
   command = "npm run build"
-  publish = "out"
-
-[[plugins]]
-  package = "@netlify/plugin-nextjs"
+  publish = "out"

package.json

@@ -12,8 +12,5 @@
     "next": "10.0.9",
     "react": "17.0.1",
     "react-dom": "17.0.1"
-  },
-  "devDependencies": {
-    "@netlify/plugin-nextjs": "^3.0.3"
   }
 }