Fix build for python 3.9

Signed-off-by: Mike Stitt <mike@stitt.cc>

Author: MikeStitt

subprojects/robotpy-wpilib/tests/test_timedrobot.py

@@ -96,7 +96,7 @@ def _onRobotInitStarted(self) -> None:
             self._robotInitStarted = True
             self._cond.notify_all()
 
-    def _robotThread(self, robot: TimedRobot | TimedRobotPy) -> None:
+    def _robotThread(self, robot: TimedRobotPy) -> None:
         with self._cond:
             self._robotStarted = True
             self._cond.notify_all()