github: Update PR template

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,21 +1,12 @@
-<!--
-Squash the commits, as appropriate. See .github/CONTRIBUTING.md for
-more information.
+##### Issue
+<!-- E.g. Fixes #1, Implements #2, etc. -->
+<!-- Or a short description, if the issue does not exist. -->
 
-Describe the relevant changes in the commit messages, if they need explaining.
- 
-If the pull request introduces a new feature or an important bug fix, consider
-adding _one_ of the below tags, enclosed in square brackets, in its title:
 
-    ENH, FIX, DOC, WIP
+##### Description of changes
 
-For some example:
 
-    [ENH] CrossValidation: Parallelize computation
-    [FIX] NaiveBayesLearner: Don't crash on input containing nan values
-    [DOC] Extend documentation for widget development
-    [WIP] Working on X ... RFC please
-
-Pull-requests not so tagged will be batched as "other features and bugfixes,"
-which is fine for stuff you don't go home and brag to your mother about.
--->
+##### Includes
+- [X] Code changes
+- [ ] Tests
+- [ ] Documentation