Add python source build

.github/workflows/build.yml

@@ -89,7 +89,7 @@ jobs:
       # Upgrade pip to the latest version.
       - name: Upgrade pip
         run: |
-          python -m pip install --upgrade pip
+          $LOCAL_PYTHON -m pip install --upgrade pip
 
       # Make sure Visual Studio build is all in place on Windows.
       - name: Setup MSVC
@@ -99,7 +99,7 @@ jobs:
       # Install dependencies required for building and testing.
       - name: Install dependencies
         run: |
-          pip install --upgrade setuptools wheel
+          $LOCAL_PYTHON -m pip install --upgrade setuptools wheel
 
       # Build the wheel package with or without nogil suffix.
       - name: Build
@@ -114,7 +114,7 @@ jobs:
       # Install the built wheel package so we can test it.
       - name: Install wheel
         run: |
-          pip install build/dist/*.whl
+          $LOCAL_PYTHON -m pip install build/dist/*.whl
         shell: bash
         working-directory: ${{github.workspace}}