Require python-dateutil>=2.8.1

[felix-hilden]

Describe the bug
When installed with python-dateutil<2.8.1, importing UnleashClient raises "cannot import ParserError from dateutil.parser".

Expected behavior
UnleashClient would have been installed with the appropriate version restriction.

Additional context
Python 3.9, but I think it doesn't make a difference. The change to dateutil is this one.

This might make older versions of UnleashClient install in favor of the newest one if solvers decide that the restricted dateutil version wouldn't fit, but it's probably better to fix the issue.

[Tymek]

Thank your for reporting this. Would you like to contribute a fix? If not, I'll add it to our priorities internally.

[felix-hilden]

I can have a look next week if you haven't gotten to it! I know very little about the project, so if it's a trivial thing, feel free to just do it 👍🏿

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[snosratiershad]

@Tymek, I've an idea. As I noticed, before 2.8.1 it raised ValueError instead of ParserError in the same cases. what if instead of requiring at least a 2.8.1 version of dateutils, check the version and use ValueError instead?

[snosratiershad]

Here's an example: #273

[snosratiershad]

As #273 merged, now we can close this issue.