Update caldav to 1.3.*

[sobolevn]

Closes #10482
Source: https://github.com/python-caldav/caldav

[tobixen]

The 1.3 release seems to be cursed ... I suppose there will be a 1.3.7-release today as well

[tobixen]

Now that the caldav library officially does not work with python2 anymore ... perhaps we could get type hints merged into the library itself? I don't feel like prioritizing it myself, but I'd gladly accept merge/pull-requests.

[AlexWaygood]

Now that the caldav library officially does not work with python2 anymore ... perhaps we could get type hints merged into the library itself? I don't feel like prioritizing it myself, but I'd gladly accept merge/pull-requests.

That would be fantastic. The pytype typechecker has a merge_pyi tool that can help with automatically integrating stubs into runtime packages. (Not promising to take this on myself either, though 😄)

[AlexWaygood]

Thanks!

[github-actions]

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉