Added info about creating a release.

Signed-off-by: Dennis Labordus <[email protected]>

Author: Dennis Labordus

docs/PULL_REQUESTS.md

@@ -25,3 +25,5 @@ The following labels cause the pull request to be ignored in the release notes:
 - ``wontfix``
 - ``duplicate``
 - ``invalid``
+
+**Remark**: The label ``tooling`` is not a standard label, so that may need to be created by the first developer using it.