add stub library for str2bool (#12260)

Author: ZivRonen

stubs/str2bool/METADATA.toml

@@ -0,0 +1,2 @@
+version = "1.1"
+upstream_repository = "https://github.com/symonsoft/str2bool"

stubs/str2bool/str2bool/__init__.pyi

@@ -0,0 +1,7 @@
+from typing import Literal, overload
+
+@overload
+def str2bool(value: str, raise_exc: Literal[True]) -> bool: ...
+@overload
+def str2bool(value: str, raise_exc: bool = False) -> bool | None: ...
+def str2bool_exc(value: str) -> bool: ...