root/pypi: links for mattermost

root/pypi mattermost-6.5.0.tar.gz
root/pypi mattermost-6.1.0.tar.gz
root/pypi mattermost-5.38.0.tar.gz
root/pypi mattermost-5.33.0.tar.gz
root/pypi mattermost-5.31.0.tar.gz