Retire runner 'macos-13'

Runner will be removed from GitHub in December and enter brownout in November

Signed-off-by: Thomas Lauf <thomas.lauf@tngtech.com>

Author: lauft

.github/workflows/cmake.yml

@@ -20,8 +20,6 @@ jobs:
             runner: macos-15
           - name: "macOS 14"
             runner: macos-14
-          - name: "macOS 13"
-            runner: macos-13
           - name: "Windows"
             runner: windows-latest
     runs-on: ${{ matrix.runner }}