Add missing default value

Author: donbarbos

stubs/reportlab/reportlab/lib/utils.pyi

@@ -86,7 +86,7 @@ class ArgvDictValue:
 def getArgvDict(**kw): ...
 def getHyphenater(hDict=None): ...
 def open_for_read_by_name(name, mode: str = "b"): ...
-def rlUrlRead(name: str, headers: MutableMapping[str, str] | None) -> _UrlopenRet: ...
+def rlUrlRead(name: str, headers: MutableMapping[str, str] | None = None) -> _UrlopenRet: ...
 def open_for_read(name, mode: str = "b"): ...
 def open_and_read(name, mode: str = "b"): ...
 def open_and_readlines(name, mode: str = "t"): ...