Limit versions of rarfile that can be used

[gene1wood]

In markokr/rarfile#70 it's reported that the custom_check function was removed from the rarfile pypi package. As a result the error reported in #1013 occurs when a version of rarfile newer than 3.1 is installed.

This fixes #1013 by limiting the range of rarfile versions.

Once the legendastv provider is changed to no longer use custom_check this version constraint could be removed.

[gene1wood]

The python 2.7 Jenkins tests are failing because of #1029
I'm unsure why the python 3 Jenkins tests are failing, they report

________________________ ERROR collecting test session _________________________

Direct construction of Pep8Item has been deprecated, please use Pep8Item.from_parent.

See https://docs.pytest.org/en/stable/deprecations.html#node-construction-changed-to-node-from-parent for more details.

However I don't see any use of from_parent in the subliminal tests

[clach04]

Alternative solution is #1045, however the setup.py in that should be updated to require >3.1

[gene1wood]

This PR is waiting on someone to begin maintaining this repo (see #1046) as otherwise there's nobody to merge it.

[getzze]

legendastv Provider was removed

[gene1wood]

@getzze Do you know what commit it was removed in? It appears to still be present and using the no longer existing custom_check method, but I could be wrong.

https://github.com/Diaoul/subliminal/blob/f86450918501ef11e26e40eef153654c52a6d8bb/subliminal/providers/legendastv.py

[ptrcnull]

it was 4130a48, but it's only on the develop branch; you'll have to wait for the new release

[getzze]

Exactly, I was trying to close old PRs, sorry for not giving more information. Thanks @ptrcnull