add default for owner parameter of pyqtSignal.__get__() (#199)

https://github.com/python-qt-tools/PyQt5-stubs/actions/runs/3485949394/jobs/5831945350#step:7:111
> `error: PyQt5.QtCore.pyqtSignal.__get__ is inconsistent, runtime
argument "owner" has a default value but stub argument does not`

Author: altendky

PyQt5-stubs/QtCore.pyi

@@ -55,11 +55,18 @@ class pyqtSignal:
 
     def __init__(self, *types: typing.Any, name: str = ...) -> None: ...
 
-    @typing.overload
-    def __get__(self, instance: None, owner: typing.Type["QObject"]) -> "pyqtSignal": ...
+    if sys.version_info >= (3, 10):
+        @typing.overload
+        def __get__(self, instance: None, owner: typing.Optional[typing.Type["QObject"]] = ...) -> "pyqtSignal": ...
 
-    @typing.overload
-    def __get__(self, instance: "QObject", owner: typing.Type["QObject"]) -> pyqtBoundSignal: ...
+        @typing.overload
+        def __get__(self, instance: "QObject", owner: typing.Optional[typing.Type["QObject"]] = ...) -> pyqtBoundSignal: ...
+    else:
+        @typing.overload
+        def __get__(self, instance: None, owner: typing.Type["QObject"]) -> "pyqtSignal": ...
+
+        @typing.overload
+        def __get__(self, instance: "QObject", owner: typing.Type["QObject"]) -> pyqtBoundSignal: ...
 
 
 # Convenient type aliases.