Wrap vobject.win32tz in platform check (#5747)

stubs/vobject/vobject/win32tz.pyi

@@ -1,39 +1,36 @@
 import datetime
+import sys
 from typing import Any
 
-handle: Any
-tzparent: Any
-parentsize: Any
-localkey: Any
-WEEKS: Any
-
-def list_timezones(): ...
-
-class win32tz(datetime.tzinfo):
-    data: Any
-    def __init__(self, name) -> None: ...
-    def utcoffset(self, dt): ...
-    def dst(self, dt): ...
-    def tzname(self, dt): ...
-
-def pickNthWeekday(year, month, dayofweek, hour, minute, whichweek): ...
-
-class win32tz_data:
-    display: Any
-    dstname: Any
-    stdname: Any
-    stdoffset: Any
-    dstoffset: Any
-    stdmonth: Any
-    stddayofweek: Any
-    stdweeknumber: Any
-    stdhour: Any
-    stdminute: Any
-    dstmonth: Any
-    dstdayofweek: Any
-    dstweeknumber: Any
-    dsthour: Any
-    dstminute: Any
-    def __init__(self, path) -> None: ...
-
-def valuesToDict(key): ...
+if sys.platform == "win32":
+    handle: Any
+    tzparent: Any
+    parentsize: Any
+    localkey: Any
+    WEEKS: Any
+    def list_timezones(): ...
+    class win32tz(datetime.tzinfo):
+        data: Any
+        def __init__(self, name) -> None: ...
+        def utcoffset(self, dt): ...
+        def dst(self, dt): ...
+        def tzname(self, dt): ...
+    def pickNthWeekday(year, month, dayofweek, hour, minute, whichweek): ...
+    class win32tz_data:
+        display: Any
+        dstname: Any
+        stdname: Any
+        stdoffset: Any
+        dstoffset: Any
+        stdmonth: Any
+        stddayofweek: Any
+        stdweeknumber: Any
+        stdhour: Any
+        stdminute: Any
+        dstmonth: Any
+        dstdayofweek: Any
+        dstweeknumber: Any
+        dsthour: Any
+        dstminute: Any
+        def __init__(self, path) -> None: ...
+    def valuesToDict(key): ...