Update github PR template (#337)

Author: Krzysztof Jan Modras

.github/pull_request_template.md

@@ -1,23 +1,12 @@
-<!--- Provide a general summary of your changes in the Title above -->
 
-## Ticket
-<!--- 
-Add a reference to the ticket this PR relates to, if any. 
-You can write 'Fixes #100' to auto close ticket #100 on merge.
-Or write 'Re #100' to reference ticket #100 without changing its status.
--->
+<!--- Add a reference to the Github issue this PR relates to, if any, eg: 'Fixes #100' -->
+Fix #
 
-## Description
-<!--- Describe your changes in detail -->
-
-## Motivation and Context
-<!--- Why is this change required? What problem does it solve? -->
-<!--- If it fixes an open issue, please link to the issue here. -->
+## Implementation details
+<!--- Provide a general summary of your changes in the Title above. Attach screenshot if relevant.-->
 
 ## Checklist:
 <!--- Go over all the following points, and put an `x` in all the boxes that apply. -->
-<!--- If you're unsure about any of these, don't hesitate to ask. We're here to help! -->
 - [ ] My squashed commit messages follows the [7 golden rules](https://chris.beams.io/posts/git-commit/)
-- [ ] My code follows the code style of this project.
 - [ ] I updated or created necessary unit tests
-- [ ] I updated all necessary documentation
+- [ ] I've tested my changes in Dark Mode, iPad, iOS <= 12, Landscape and in German