Bump simplejson to 3.19.* (#10049)

stubs/simplejson/METADATA.toml

@@ -1,4 +1,4 @@
-version = "3.18.*"
+version = "3.19.*"
 
 [tool.stubtest]
 ignore_missing_stub = true

stubs/simplejson/simplejson/encoder.pyi

@@ -5,6 +5,6 @@ class JSONEncoder:
     def __init__(self, *args: Any, **kwargs: Any) -> None: ...
     def encode(self, o: Any) -> str: ...
     def default(self, o: Any) -> NoReturn: ...
-    def iterencode(self, o: Any, _one_shot: bool = False) -> Iterator[str]: ...
+    def iterencode(self, o: Any) -> Iterator[str]: ...
 
 class JSONEncoderForHTML(JSONEncoder): ...