Bump iso8601 from 1.1.0 to 2.1.0

Bumps [iso8601](https://github.com/micktwomey/pyiso8601) from 1.1.0 to 2.1.0.
- [Release notes](https://github.com/micktwomey/pyiso8601/releases)
- [Changelog](https://github.com/micktwomey/pyiso8601/blob/main/CHANGELOG.md)
- [Commits](micktwomey/pyiso8601@1.1.0...2.1.0)

---
updated-dependencies:
- dependency-name: iso8601
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

setup.py

@@ -117,7 +117,7 @@ def readme():
         "typing_extensions==4.8.0",
         "charset-normalizer>=2.0.7",
         "ciso8601==2.3.0",
-        "iso8601==1.1.0",
+        "iso8601==2.1.0",
         "pgpy==0.6.0",
         "python-magic==0.4.27",
         "dateparser==1.1.8",