Rename pull_request_template.md to PULL_REQUEST_TEMPLATE.md

Renaming to an all caps file name to align with other projects with Hyku's ALL_CAPS filenames in the .github directory

Author: DiemBTran

.github/pull_request_template.md renamed to .github/PULL_REQUEST_TEMPLATE.md

@@ -13,4 +13,4 @@ Refs #issuenumber
 
 </details>
 
-# Notes
+# Notes