CI: Pinning coverage < 5.0

[tk0miya]

Feature or Bugfix

• Testing

Purpose

• Pinning coverage < 5.0
• It seems our testing has failed since the package updated.
• This tries to confirm the reason of error with pinning the package to old one.

[jfbu]

I don't know why but despite

Installing collected packages: toml, filelock, tox, idna, urllib3, chardet, requests, coverage, codecov

Successfully installed chardet-3.0.4 codecov-2.0.15 coverage-4.5.4 filelock-3.0.12 idna-2.8 requests-2.22.0 toml-0.10.0 tox-3.14.2 urllib3-1.25.7

one sees later

du15 installed: alabaster==0.7.12,attrs==19.3.0,Babel==2.7.0,certifi==2019.11.28,chardet==3.0.4,coverage==5.0,docutils==0.15,docutils-stubs==0.0.21,entrypoints==0.3

adn then testing fails.

[tk0miya]

As expected, this works fine!