Lint trailing whitespace (#3230)

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,4 +1,4 @@
-# What does this implement/fix? 
+# What does this implement/fix?
 
 Quick description and explanation of changes
 
@@ -35,6 +35,6 @@ Quick description and explanation of changes
 ## Checklist:
   - [ ] The code change is tested and works locally.
   - [ ] Tests have been added to verify that the new code works (under `tests/` folder).
-  
+
 If user exposed functionality or configuration variables are added/changed:
   - [ ] Documentation added/updated in [esphome-docs](https://github.com/esphome/esphome-docs).