upgrade macos runner for python x86_64 builds

ref PyO3/maturin#2255

Author: 2bndy5

.github/workflows/python-packaging.yml

@@ -130,7 +130,7 @@ jobs:
       fail-fast: false
       matrix:
         platform:
-          - runner: macos-12
+          - runner: macos-13
             target: x86_64
           - runner: macos-14
             target: aarch64