only depend on backports-strenum on Python < 3.11 (#1309)

Author: dotlambda

poetry.lock

@@ -20,7 +20,7 @@ backoff = ">=1.10.0,<3.0"
 attrs = ">=21.2,<24.0"
 boto3 = "^1.18.59"
 warrant-lite = "^1.0.4"
-backports-strenum = "^1.2.4"
+backports-strenum = { version = "^1.2.4", python = "<3.11" }
 
 [tool.poetry.dev-dependencies]
 tox = "^4.16"