Prepare release v9.1.1 #3

Job	Run time
Perform checks before releasing	2s
tests (ubuntu-latest, 2.7)	1m 1s
tests (ubuntu-latest, 3.0)	49s
tests (ubuntu-latest, 3.1)	52s
tests (ubuntu-latest, 3.2)	45s
tests (macos-latest, 2.7)	1m 47s
tests (macos-latest, 3.0)	2m 9s
tests (macos-latest, 3.1)	1m 33s
tests (macos-latest, 3.2)	1m 12s
tests (windows-latest, 2.7)	4m 43s
tests (windows-latest, 3.0)	4m 8s
tests (windows-latest, 3.1)	5m 11s
tests (windows-latest, 3.2)	5m 23s
tests (ubuntu-latest, jruby-9.4)	8m 55s
Publish Ruby Gem	6s
Create GitHub Release and Git tag	10s
	38m 46s

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