docs: update .all-contributorsrc [skip ci]

Author: allcontributors[bot]

.all-contributorsrc

@@ -297,6 +297,15 @@
  "contributions": [
  "code"
  ]
+ },
+ {
+ "login": "nikunjagarwal321",
+ "name": "Nikunj Agarwal",
+ "avatar_url": "https://avatars0.githubusercontent.com/u/35420775?v=4",
+ "profile": "http://www.nikunjagarwal.social",
+ "contributions": [
+ "code"
+ ]
  }
  ],
  "contributorsPerLine": 7,