docs: add Upendra-Allagadda as a contributor for doc (#2647)

* docs: update README.md [skip ci]

* docs: update .all-contributorsrc [skip ci]

---------

Co-authored-by: allcontributors[bot] <46447321+allcontributors[bot]@users.noreply.github.com>

.all-contributorsrc

@@ -2641,7 +2641,16 @@
       "contributions": [
         "doc",
         "code"
-      ]      
+      ]
+    },
+    {
+      "login": "Upendra-Allagadda",
+      "name": "Allagadda Sai Upendranath",
+      "avatar_url": "https://avatars.githubusercontent.com/u/25962010?v=4",
+      "profile": "https://github.com/Upendra-Allagadda",
+      "contributions": [
+        "doc"
+      ]
     }
   ],
   "contributorsPerLine": 7,