chore: remove testruns for symfony 6.3 (#81)

Co-authored-by: Christopher Georg <[email protected]>

Author: Chris53897

.github/workflows/ci.yaml

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