Fix typo simple_reference docstring, fix workflows to use python 3.11 by default #926

Job	Run time
tutorial-test (3.8, Tianshou)	4m 47s
tutorial-test (3.8, CustomEnvironment)	55s
tutorial-test (3.8, CleanRL)	8m 21s
tutorial-test (3.8, SB3/kaz)	7m 29s
tutorial-test (3.8, SB3/waterworld)	8m 27s
tutorial-test (3.8, SB3/connect_four)	4m 2s
tutorial-test (3.8, SB3/test)	3m 37s
tutorial-test (3.8, AgileRL)	3m 13s
tutorial-test (3.9, Tianshou)	3m 22s
tutorial-test (3.9, CustomEnvironment)	27s
tutorial-test (3.9, CleanRL)	5m 39s
tutorial-test (3.9, SB3/kaz)	6m 54s
tutorial-test (3.9, SB3/waterworld)	7m 47s
tutorial-test (3.9, SB3/connect_four)	3m 46s
tutorial-test (3.9, SB3/test)	2m 2s
tutorial-test (3.9, AgileRL)	4m 14s
tutorial-test (3.10, Tianshou)	3m 16s
tutorial-test (3.10, CustomEnvironment)	39s
tutorial-test (3.10, CleanRL)	7m 5s
tutorial-test (3.10, SB3/kaz)	7m 4s
tutorial-test (3.10, SB3/waterworld)	12m 0s
tutorial-test (3.10, SB3/connect_four)	2m 48s
tutorial-test (3.10, SB3/test)	2m 7s
tutorial-test (3.10, AgileRL)	8m 55s
tutorial-test (3.11, Tianshou)	5m 43s
tutorial-test (3.11, CustomEnvironment)	58s
tutorial-test (3.11, CleanRL)	9m 32s
tutorial-test (3.11, SB3/kaz)	6m 43s
tutorial-test (3.11, SB3/waterworld)	12m 17s
tutorial-test (3.11, SB3/connect_four)	4m 17s
tutorial-test (3.11, SB3/test)	3m 24s
tutorial-test (3.11, AgileRL)	4m 30s
	2h 46m 20s

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