Update test-build.yml

Author: yeager

.github/workflows/test-build.yml

@@ -19,7 +19,7 @@ jobs:
     steps:
       - uses: actions/setup-python@master
         with:
-          python-version: 3.12  # pinned for Sphinx 3.4.3 to build 3.10
+          python-version: 3.14  # pinned for Sphinx 3.4.3 to build 3.10
       - uses: actions/checkout@master
         with:
           repository: python/cpython