Bump python-crontab to 3.1.* (#12008)

stubs/python-crontab/METADATA.toml

@@ -1,2 +1,2 @@
-version = "3.0.*"
+version = "3.1.*"
 upstream_repository = "https://gitlab.com/doctormo/python-crontab"

stubs/python-crontab/crontab.pyi

@@ -259,6 +259,7 @@ class CronSlice:
     def __iter__(self) -> Iterator[int]: ...
     def __len__(self) -> int: ...
     def parse_value(self, val: str, sunday: int | None = ...) -> int | CronValue: ...
+    def test_value(self, value: str, sunday: int | None = None) -> str: ...
 
 def get_cronvalue(value: int, enums: list[str]) -> int | CronValue: ...