pyproject: pass $PKGCRAFT_C_REF through to cibuildwheel container env

Author: radhermit

pyproject.toml

@@ -73,6 +73,7 @@ exclude_lines = [
 build = ["cp39-*", "cp310-*", "cp311-*"]
 build-frontend = "build"
 build-verbosity = 1
+environment-pass = ["PKGCRAFT_C_REF"]
 before-all = "{package}/.ci/buildlib"
 test-requires = "pytest"
 test-command = "PYTEST_DISABLE_PLUGIN_AUTOLOAD=1 pytest {package}/tests"