Merge pull request #180 from aws-geospatial/tjmichaels-patch-1

Update CONTRIBUTING.md for abandoned PRs

CONTRIBUTING.md

@@ -35,7 +35,9 @@ To send us a pull request, please:
 4. Commit to your fork using clear commit messages.
 5. Send us a pull request, answering any default questions in the pull request interface.
 6. Pay attention to any automated CI failures reported in the pull request, and stay involved in the conversation.
-
+7. After 4 weeks of inactivity after a request for changes or additional information on a pull
+   request, the request is eligible to be closed as an abandonded pull request.
+
 GitHub provides additional document on [forking a repository](https://help.github.com/articles/fork-a-repo/) and
 [creating a pull request](https://help.github.com/articles/creating-a-pull-request/).