Update readme for recent CI changes

README.rst

@@ -182,9 +182,13 @@ Developer Notes
             print(sys.path)
 
 - Gitlab CI Setup:
+    - The ``build`` stage has to be triggered manually when something in the setup changes. This is because it takes a fair amount of time.
     - In ``~/.gitlab-runner/config.toml`` (for the runner):
         - change priviliges to true
         - Use local images: ``pull_policy = "if-not-present"``
+        - To ``[[runners]]`` add ``environment = ["DOCKER_TLS_CERTDIR="]```
+            - See https://gitlab.com/gitlab-org/gitlab-ce/issues/64959
+
     - Run local: ``gitlab-runner exec docker --docker-privileged build`` or with ``build`` replaced by job name
         - maybe local vars have to be change to use local Docker images because ``CI_REGISTRY``,... are not set