Steps to replicate the issue (include links if applicable):
dev-requirements.txt requites codecov package
https://codesearch.wmcloud.org/pywikibot/?q=codecov&files=&excludeFiles=&repos=
What happens?:
Seems that packages is not available any longer:
ERROR: Could not find a version that satisfies the requirement codecov (from versions: none)
Found on any CI test (Github and Appveyor)
https://pypi.org/search/?q=codecov
Other information
https://docs.codecov.com/docs/deprecated-uploader-migration-guide#python-uploader
https://github.com/codecov/example-python/