Remove unused CIBW_PROJECT_REQUIRES_PYTHON environment variable

Author: molinav

.github/workflows/build.yml

@@ -93,7 +93,6 @@ jobs:
       - name: Build wheels
         uses: pypa/[email protected]
         env:
-          CIBW_PROJECT_REQUIRES_PYTHON: ">=3.9"
           CIBW_ARCHS_LINUX: auto64
           CIBW_BUILD_VERBOSITY: 1
           CIBW_BUILD: "cp39* cp310* cp311* cp312*"