ref(scope): Broaden add_attachment type (getsentry#3342)

Update the type hint to clarify that `add_attachment`'s `bytes`
parameter can also accept `Callable[[], bytes]` values, since it
gets passed through to the `Attachment` constructor, which accepts
such values.

Author: szokeasaurusrex

sentry_sdk/scope.py

@@ -893,7 +893,7 @@ def clear_breadcrumbs(self):
 
     def add_attachment(
         self,
-        bytes=None,  # type: Optional[bytes]
+        bytes=None,  # type: Union[None, bytes, Callable[[], bytes]]
         filename=None,  # type: Optional[str]
         path=None,  # type: Optional[str]
         content_type=None,  # type: Optional[str]