correct branch name

Author: RolandJentschETAS

process/process_areas/release_management/release_concept.rst

@@ -112,10 +112,9 @@ Branching Strategy
 
 Branches:
 
-* master: for implementation and documentation in development phase.
+* main: for implementation and documentation in development phase.
 * release/\*: Branches for distinct releases, named release/<version-number>, no functional changes, only bugfixes, quality and documentation improvements.
 
-
 Workflow:
 
 #. When ready for a new release, create a branch release/<version-number> from master (if needed).