Update user guide for branch protections

Author: ArBridgeman

doc/changes/unreleased.md

@@ -2,4 +2,8 @@
 
 ## Bugfixes
 
-* #489: Fixed .pre-commit-config.yaml to use existing nox tasks
+* #489: Fixed .pre-commit-config.yaml to use existing nox tasks
+
+## Documentation
+
+* #488: Updated user guide to make clearer under which conditions branch protections based on GitHub actions can be enacted

doc/user_guide/workflows.rst

@@ -44,3 +44,6 @@ The exasol-toolbox ships with various GitHub workflow templates. To leverage the
 ++++++++++++++++++++++++++++
 
 The best and most maintainable way to have solid branch protection (:code:`Settings/Branches/main`) is to require the workflow :code:`CI / Allow Merge` to pass successfully.
+
+.. note::
+   Setting the required status checks to pass before merging is only possible after running a CI build at **least once** on the affected branch.