ci: drop macOS builder back to macOS 13

Something seems to have changed with macOS' FAT32 implementation with
macOS 14 that is causing FAT32-related tests to fail. We need to
investigate further, but this shouldn't affect most users.

Signed-off-by: Jacob Howard <[email protected]>

Author: xenoscopic

.github/workflows/ci.yml

@@ -25,7 +25,7 @@ jobs:
           scripts/ci/verify_commits.sh
   macos:
     name: macOS
-    runs-on: macos-latest
+    runs-on: macos-13
     timeout-minutes: 90
     steps:
       - uses: actions/checkout@v2