Pin Python version at 3.11 in build workflow

Python 3.12.x is incompatible with the current version of node-gyp (9.4.0). For this reason, it is necessary to
configure the "GitHub Actions" workflow to use the compatible Python 3.11.x until the next release of node-gyp (which
should contain a fix for the breakage) is made.

.github/workflows/build.yml

@@ -304,7 +304,7 @@ jobs:
         if: fromJSON(matrix.config.container).image == null
         uses: actions/setup-python@v4
         with:
-          python-version: '3.x'
+          python-version: '3.11.x'
 
       - name: Install Go
         uses: actions/setup-go@v4