docs: add contribute page in toctree (#638)

Co-authored-by: pyansys-ci-bot <[email protected]>

Author: Revathyvenugopal162

doc/changelog.d/638.documentation.md

@@ -0,0 +1 @@
+docs: add contribute page in toctree

doc/source/index.rst

@@ -36,6 +36,12 @@ are included in the theme to make documentation more appealing and user-friendly
 
         {% endif %}
 
+        .. grid-item-card:: :material-regular:`people;1.25em` Contribute
+            :link: contribute
+            :link-type: doc
+
+            Learn how to contribute to the Ansys Sphinx Theme.
+
         .. grid-item-card:: :material-regular:`update;1.25em` Changelog
             :link: changelog
             :link-type: doc