Fix iOS dinghy test in CI

Author: madsmtm

.github/workflows/ci.yml

@@ -505,7 +505,7 @@ jobs:
     # if: ${{ env.FULL }}
     if: ${{ github.head_ref == 'new-versions' || github.ref_name == 'ci-full' }}
     name: Test on iOS simulator w. dinghy
-    runs-on: macos-11
+    runs-on: macos-13
     needs:
     - fmt
     - lint