tests: set EMAIL for Git commit test_push_on_locked_repo_by_other_user_git - it _is_ necessary on some machines 7db1bcf1d95b too aggressively removed setting EMAIL (which was set in a way that didn't work on Windows). On some machines the git commit in _add_files_and_push would fail with 'Please tell me who you are' and the actual test check of "Repository %s locked by user" would fail. On other machines - also without any local git configuration - it works fine. https://git-scm.com/book/en/v2/Git-Internals-Environment-Variables#Committing suggests that it might be a good idea to set it ... so let's do it. (Patch modified by Mads Kiilerich)

# requirements.txt file for use as "pip install -r requirements.txt" as a
# readthedocs compatible alternative to "pip install -e ." which is a working
# alternative to "setup.py develop" which doesn't work with Mercurial 3.7
.