COMP: Install specific XCode version for Python packages

To be compatible with the ITKPythonBuilds, which are not built against
the same version.

xref: actions/runner-images#2056
xref: https://github.com/actions/virtual-environments/blob/main/images/macos/macos-10.15-Readme.md#xcode

Author: thewtex

.github/workflows/build-test-package.yml

@@ -192,6 +192,10 @@ jobs:
     steps:
     - uses: actions/checkout@v2
 
+    - name: 'Specific XCode version'
+      run: |
+        sudo xcode-select -s "/Applications/Xcode_11.7.app"
+
     - name: Get specific of CMake, Ninja
       uses: lukka/[email protected]
 

{{cookiecutter.project_name}}/.github/workflows/build-test-package.yml

@@ -177,6 +177,10 @@ jobs:
     steps:
     - uses: actions/checkout@v2
 
+    - name: 'Specific XCode version'
+      run: |
+        sudo xcode-select -s "/Applications/Xcode_11.7.app"
+
     - name: Get specific of CMake, Ninja
       uses: lukka/[email protected]