Update croniter requirement from ==2.0.* to >=2.0,<3.1

Updates the requirements on [croniter](https://github.com/kiorky/croniter) to permit the latest version.
- [Changelog](https://github.com/kiorky/croniter/blob/master/CHANGELOG.rst)
- [Commits](kiorky/croniter@2.0.0...3.0.3)

---
updated-dependencies:
- dependency-name: croniter
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

setup.py

@@ -20,7 +20,7 @@
     install_requires=[
         "psycopg2-binary==2.9.*",
         "pyyaml==6.0.*",
-        "croniter==2.0.*",
+        "croniter>=2.0,<3.1",
         "tabulate==0.9.*",
         "slack-sdk==3.31.*",
         "backoff==2.2.*",