PR-Template Updated

Graph Control supported SDK link has been updated. We will include the Graph Repo Guideline link once we create one.

Author: Kyaa-dost

.github/PULL_REQUEST_TEMPLATE.md

@@ -26,8 +26,7 @@ What kind of change does this PR introduce?
 
 Please check if your PR fulfills the following requirements:
 
-- [ ] Tested code with current [supported SDKs](../readme.md#supported)
-- [ ] Pull Request has been submitted to the documentation repository [instructions](..\contributing.md#docs). Link: <!-- docs PR link -->
+- [ ] Tested code with current [supported SDKs](https://github.com/windows-toolkit/Graph-Controls/blob/master/README.md)
 - [ ] Sample in sample app has been added / updated (for bug fixes / features)
     - [ ] Icon has been created (if new sample) following the [Thumbnail Style Guide and templates](https://github.com/windows-toolkit/WindowsCommunityToolkit-design-assets)
 - [ ] Tests for the changes have been added (for bug fixes / features) (if applicable)