create pull request template

Author: andrey1s

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,10 @@
+| Q             | A
+| ------------- | ---
+| Bug fix?      | [yes|no]
+| New feature?  | [yes|no]
+| BC breaks?    | [yes|no]
+| Deprecations? | [yes|no]
+| Tests pass?   | [yes|no]
+| Fixed tickets | [comma-separated list of tickets fixed by the PR, if any]
+| License       | MIT
+| Doc PR        | [reference to the documentation PR, if any]