Update PR template (#73)

Author: uurien

.github/pull_request_template.md

@@ -10,22 +10,9 @@
 
 <!-- Anything else we should know when reviewing? -->
 
-### Describe how to test your changes
-
-<!--
-Write here in detail how you have tested your changes
-and instructions on how this should be tested in QA.
-
-Describe or link instructions to set up environment
-for testing, if the process requires more than just
-running on one of the supported platforms.
--->
-
 ### Checklist
 
 <!-- Place an '[x]' (no spaces) in all applicable fields. Please remove unrelated fields. -->
 
-- [ ] The CHANGELOG.md has been updated
 - [ ] Unit tests have been updated and pass
-- [ ] If known, an appropriate milestone has been selected