Bump mypy to 0.981 (#8796)

stubs/html5lib/html5lib/_inputstream.pyi

@@ -72,7 +72,7 @@ class HTMLBinaryInputStream(HTMLUnicodeInputStream):
     def detectEncodingMeta(self): ...
 
 class EncodingBytes(bytes):
-    def __new__(cls, value): ...
+    def __new__(self, value): ...
     def __init__(self, value) -> None: ...
     def __iter__(self): ...
     def __next__(self): ...