CI: macos-13 runner is retired

Author: astraw

.github/workflows/test.yml

@@ -18,7 +18,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-13, macos-latest, windows-latest]
+        os: [ubuntu-latest, macos-latest, windows-latest]
         python-version: [ '3.9', '3.x' ]
 
     steps: