correct branch name

Author: RolandJentschETAS

process/process_areas/release_management/release_concept.rst

@@ -117,6 +117,6 @@ Branches:
 
 Workflow:
 
-#. When ready for a new release, create a branch release/<version-number> from master (if needed).
+#. When ready for a new release, create a branch release/<version-number> from main (if needed).
 #. Perform final testing and adjustments on the release branch (test results should be available continuously, but maybe not all).
 #. Tag the release in the release branch.