Fix MACOSX_DEPLOYMENT_TARGET issue

Author: WillAyd

.github/workflows/python.yml

@@ -175,7 +175,7 @@ jobs:
       ARROW_BUILD_TESTS: OFF
       PYARROW_TEST_LARGE_MEMORY: ON
       # Current oldest supported version according to https://endoflife.date/macos
-      MACOSX_DEPLOYMENT_TARGET: 12.0
+      MACOSX_DEPLOYMENT_TARGET: "12.0"
     steps:
       - name: Checkout Arrow
         uses: actions/checkout@v5