Use GitHub's setup-python action to make sure a specific Python versi…

…on is used, also remove uv cache option

Signed-off-by: Matthew J. Milner <[email protected]>

.github/workflows/build.yml

@@ -40,9 +40,11 @@ jobs:
 
     - name: Install uv
       uses: astral-sh/setup-uv@v2
+
+    - name: "Set up Python"
+      uses: actions/setup-python@v5
       with:
-        enable-cache: true
-        cache-dependency-glob: "uv.lock"
+        python-version-file: ".python-version"
 
     - name: Install Sphinx and requirements
       run: uv pip install --system --break-system-packages -r pyproject.toml