CI: macos-12 is no longer supported

Signed-off-by: Nicola Murino <[email protected]>

.github/workflows/release.yml

@@ -227,7 +227,7 @@ jobs:
 
   prepare-mac:
     name: Prepare macOS binaries
-    runs-on: macos-12
+    runs-on: macos-13
 
     steps:
       - uses: actions/checkout@v4