chore: add plugin to nx.json plugins

Author: BioPhoton

nx.json

@@ -150,6 +150,9 @@
     "releaseTagPattern": "v{version}"
   },
   "plugins": [
+    {
+      "plugin": "@code-pushup/nx-plugin"
+    },
     {
       "plugin": "@push-based/nx-verdaccio",
       "options": {