Fix errors on AppVeyor by updating pip packages

[itchyny]

This pull request fixes the error on AppVeyor by updating the pip packages.

[coveralls]

Coverage remained the same at 84.134% when pulling 8c522a2 on itchyny:update-pip-packages-20200612 into d18b2d0 on stedolan:master.

[itchyny]

There's no difference in output of build_mantests.py, build_manpage.py. The difference of build_website.py is as follows. This contains a small fix against the incorrect em tag at https://github.com/stedolan/jq/blob/76c044f301c3d33b122974e405a80f2b0775dce7/manual/v1.6/index.html#L5499-L5503.

diff -r output/manual/v1.5/index.html output2/manual/v1.5/index.html
4910,4913c4910,4915
< <p>where:
< <em> STRING, REGEX and FLAGS are jq strings and subject to jq string interpolation;
< </em> REGEX, after string interpolation, should be a valid PCRE regex;
< * FILTER is one of <code>test</code>, <code>match</code>, or <code>capture</code>, as described below.</p>
---
> <p>where:</p>
> <ul>
> <li>STRING, REGEX and FLAGS are jq strings and subject to jq string interpolation;</li>
> <li>REGEX, after string interpolation, should be a valid PCRE regex;</li>
> <li>FILTER is one of <code>test</code>, <code>match</code>, or <code>capture</code>, as described below.</li>
> </ul>
diff -r output/manual/v1.6/index.html output2/manual/v1.6/index.html
5499,5502c5499,5504
< <p>where:
< <em> STRING, REGEX and FLAGS are jq strings and subject to jq string interpolation;
< </em> REGEX, after string interpolation, should be a valid PCRE regex;
< * FILTER is one of <code>test</code>, <code>match</code>, or <code>capture</code>, as described below.</p>
---
> <p>where:</p>
> <ul>
> <li>STRING, REGEX and FLAGS are jq strings and subject to jq string interpolation;</li>
> <li>REGEX, after string interpolation, should be a valid PCRE regex;</li>
> <li>FILTER is one of <code>test</code>, <code>match</code>, or <code>capture</code>, as described below.</li>
> </ul>

[itchyny]

In this branch the AppVeyor CI staill fails but merging with #2193 should fix. Please confirm https://ci.appveyor.com/project/itchyny/jq/builds/35632771. Please consider including, the CI has been failing for months.

[itchyny]

Aha, AppVeyor CI is now back to green! The problem is that I am not familiar with pacman/Windows so not sure whether my fix is the correct way 🤔 . Are there anyone familiar with pacman/Windows?

[itchyny]

After unmaintained for a few months, now this branch gets failure again. I'm not familiar with pacman packages, get tired of tackling the problem. Is there anyone kindly look into the problem?

[itchyny]

Closing due to conflict and inactivity. Hope someone familiar with Windows can fix the problem.