.gitlab-ci.yml: add comment about disabling the step `mypy-windows`

.gitlab-ci.yml

@@ -45,6 +45,12 @@ mypy:
     - python -m pip install mypy
     - PYTHONPATH=".:$PYTHONPATH" mypy --conf mypy.ini kamzik3
 
+# Below is commented out because the Windows runner is not yet available
+# see rt #1140128 (Philipp also cc'ed in the ticket)
+# answer from Elena (gitlab.service@desy.de) from 4 May 2022: "The docker-windows runner
+# was once registered in GitLab, but it has never worked so far, we are still on it. We
+# will assign your project as soon as the runner is available."
+
 #mypy-windows:
 #  image: python:3.9-windowsservercore
 #  tags: