add a PR template

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,34 @@
+<!--
+
+Thanks for wanting to contribute to PyVISA-py :)
+
+Here's some guidelines to help the review process go smoothly.
+
+1. Please write a description in this text box of the changes that are being
+   made.
+
+2. Please ensure that the code is properly formatted and typed by running
+   black, isort, flake8 and mypy.
+
+3. Please ensure that you have written units tests for the changes made/features
+   added if possible. If it is not possible please be sure to provide sufficient
+   details inline justifying the change, as it can sometimes be hard to track
+   changes made to support a particular behavior in an instrument.
+
+4. If you are closing an issue please use one of the automatic closing words as
+   noted here: https://help.github.com/articles/closing-issues-using-keywords/
+
+5. Once review has taken place please do not add features or make changes out of
+   the scope of those requested by the reviewer (doing this just add delays as
+   already reviewed code ends up having to be re-reviewed/it is hard to tell
+   what is new etc!).
+
+Many thanks in advance for your cooperation!
+
+-->
+
+- [ ] Closes # (insert issue number if relevant)
+- [ ] Executed ``black . && isort -c . && flake8`` with no errors
+- [ ] The change is fully covered by automated unit tests
+- [ ] Documented in docs/ as appropriate
+- [ ] Added an entry to the CHANGES file