Revert PULL_REQUEST_TEMPLATE

Issue gh-1618

Author: rwinch

.github/PULL_REQUEST_TEMPLATE.md

@@ -3,7 +3,5 @@ For Security Vulnerabilities, please use https://pivotal.io/security#reporting
 -->
 
 <!--
-Before creating new features, we recommend creating an issue to discuss the feature. This ensures that everyone is on the same page before extensive work is done.
-
-Thanks for contributing to Spring Security. Please provide a brief description of your pull-request and reference any related issue numbers (prefix references with gh-).
+Thanks for contributing to Spring Session. Please provide a brief description of your pull-request and reference any related issue numbers (prefix references with #).
 -->