Support python 3.11 in CI (#2461)

This PR makes a change to the task state enum so that it renders the same across all Python versions, the same as pre-3.11. Python 3.11 changes how enumerations are rendered by default by __str__ to support a usecase that is not relevant here (to support porting from int constants to enums).

.github/workflows/ci.yaml

@@ -10,7 +10,7 @@ jobs:
   main-test-suite:
     strategy:
       matrix:
-        python-version: ["3.7", "3.8", "3.9", "3.10"]
+        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11"]
     runs-on: ubuntu-20.04
     timeout-minutes: 30
 

parsl/dataflow/states.py

@@ -63,6 +63,9 @@ class States(IntEnum):
     anything about task success or failure, merely that the wrapper
     ran long enough to record it as finished."""
 
+    def __str__(self) -> str:
+        return self.__class__.__name__ + "." + self.name
+
 
 FINAL_STATES = [States.exec_done, States.memo_done, States.failed, States.dep_fail]
 """States from which we will never move to another state, because the job has