Merge pull request #1318 from sjwarner-bp/nitpick-pr-template

remove reference to xjava

.github/PULL_REQUEST_TEMPLATE.md

 
 Reviewer Resources:
 
-[Track Policies](https://github.com/exercism/xjava/blob/master/POLICIES.md#event-checklist)
+[Track Policies](https://github.com/exercism/java/blob/master/POLICIES.md#event-checklist)