chore: remove testruns for symfony 6.3 (#161)

Co-authored-by: Christopher Georg <christopher.georg@sr-travel.de>

Author: Chris53897

.github/workflows/ci.yaml

@@ -18,7 +18,6 @@ jobs:
           - ''
         symfony:
           - '5.4.*'
-          - '6.3.*'
           - '6.4.*'
           - '7.0.*'
         include: