`please-test` label: how and when to use it

I couldn't figure out whether to put this here or in our https://github.com/dwyl/ateam-master-reference repo, but either way, reference will need to be made to it from https://github.com/dwyl/contributing

There seems to be some confusion at dwyl around how and when to use the `please-test` label, as well as what it means.

The over-arching process is, **once PR is merged:**
+ **Developer** :arrow_right: Deploy to staging area of project (if not already done automatically)
+ **Developer** :arrow_right: Quick manual test to ensure functionality has been deployed correctly as is in fact ready for review by product owner (PO) as nothing is more annoying than being asked to test something that is obviously not working
+ **Developer** :arrow_right: If ready to be tested by PO, add `please-test` label and *assign* to PO
+ **PO** :arrow_right: Test feature
+ *If working as expected*, close issue
+ *If not working as expected*:
+ Write description of steps taken to test feature
+ Write description of results, preferably accompanied by screenshot where relevant
+ *Remove* `please-test` label
+ Assign back to developer

Process starts again as if a new, high priority issue.

**Other points:**
+ Only *user stories* should be moved to `please-test` and assigned to PO, `technical` tasks are closed by the developers who opened them.