Apply ruff/Pylint rule PLR6201

PLR6201 Use a set literal when testing for membership

Author: DimitriPapadopoulos

setup.py

@@ -4,7 +4,7 @@
 if vi < (3, 8):
     raise RuntimeError('uvloop requires Python 3.8 or greater')
 
-if sys.platform in ('win32', 'cygwin', 'cli'):
+if sys.platform in {'win32', 'cygwin', 'cli'}:
     raise RuntimeError('uvloop does not support Windows at the moment')
 
 import os

tests/test_tcp.py

@@ -45,7 +45,7 @@ def eof_received(self):
         self.state = 'EOF'
 
     def connection_lost(self, exc):
-        assert self.state in ('CONNECTED', 'EOF'), self.state
+        assert self.state in {'CONNECTED', 'EOF'}, self.state
         self.state = 'CLOSED'
         if self.done:
             self.done.set_result(None)