docs: update .all-contributorsrc

.all-contributorsrc

       "contributions": [
         "doc"
       ]
+    },
+    {
+      "login": "marconett",
+      "name": "Marco",
+      "avatar_url": "https://avatars1.githubusercontent.com/u/3315507?v=4",
+      "profile": "https://marco-nett.de",
+      "contributions": [
+        "doc"
+      ]
     }
   ],
   "contributorsPerLine": 7