docs: update .all-contributorsrc [skip ci]

allcontributors[bot] · AlexV525 · commit 703ab8a1a99f · 2020-07-12T15:12:57.000+08:00
diff --git a/.all-contributorsrc b/.all-contributorsrc
@@ -31,6 +31,17 @@
         "example",
         "ideas"
       ]
+    },
+    {
+      "login": "SchnMar",
+      "name": "Marcel Schneider",
+      "avatar_url": "https://avatars3.githubusercontent.com/u/12902321?v=4",
+      "profile": "https://github.com/SchnMar",
+      "contributions": [
+        "bug",
+        "code",
+        "ideas"
+      ]
     }
   ],
   "contributorsPerLine": 7,
