Fix "shutdown_timeout" typing (#1256)

Change "shutdown_timeout" typing from `int` -> `float`

Author: seedofjoy

sentry_sdk/consts.py

@@ -52,7 +52,7 @@ def __init__(
         release=None,  # type: Optional[str]
         environment=None,  # type: Optional[str]
         server_name=None,  # type: Optional[str]
-        shutdown_timeout=2,  # type: int
+        shutdown_timeout=2,  # type: float
         integrations=[],  # type: Sequence[Integration]  # noqa: B006
         in_app_include=[],  # type: List[str]  # noqa: B006
         in_app_exclude=[],  # type: List[str]  # noqa: B006