patch rules_python package to set shebang
this patch is applied by bazel, not portage
--- python/private/py_runtime_info.bzl
+++ python/private/py_runtime_info.bzl
@@ -15,7 +15,7 @@
 
 load(":util.bzl", "define_bazel_6_provider")
 
-DEFAULT_STUB_SHEBANG = "#!/usr/bin/env python3"
+DEFAULT_STUB_SHEBANG = "#!@PYTHON@"
 
 _PYTHON_VERSION_VALUES = ["PY2", "PY3"]