Fix visdom bug

[louis-she]

Fixes #2745

It's a bug of visdom 0.2.2 fossasia/visdom#878 , they already released 0.2.2.post1 to fix it. Actually rerunning the tests without pip cache will automatically solve the import error since we are not pinning the version in requirements-dev.txt, so it will get the fixed version.

But after updating to 0.2.2.post1 tests still fail due to another error, see the code changed.

visdom is frequently doing some code refactoring, I'm afraid some errors may occur for the same reason in the future. Should we pin the version or just let the CI fail and fix it?

@vfdev-5

[louis-she]

I've pinned the version of visdom in requirements-dev.txt or some tests will fail due to getting the previous version.

[vfdev-5]

@louis-she thanks a lot for the fixes !
I agree with you that we can fix a version and once they stabilized the code (one day) we can remove the pinning condition.

[louis-she]

The failed test seems not to be relative to the changes. Can we retrigger the failed workflow again? I can not find the rerun button. @vfdev-5

[vfdev-5]

Thanks a lot for the PR, @louis-she !