docs(contributing): move to own directory

docs/latest/README.md

@@ -40,7 +40,7 @@ Check out these helpful links:
 - Ready to dive into some code? Check out our
   [Getting Started Guide](./essentials/getting-started.md).
 - We're an active, vibrant community.
-  [Learn how you can be more involved.](./contributing.md)
+  [Learn how you can be more involved.](./contributing/index.md)
 - Feeling lost? Read our [help page](./help.md).
 
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