Install with upgrade enabled for pip
Install with upgrade enabled for pip

This ensures that the latest available version is being used.
Otherwise pip will keep the current version if it satisfies the
foo>=X value it is given.

For foo==X, -U does nothing so it is safe to always include the
flag.

scottclowe/python-continuous-integration,scottclowe/python-continuous-integration,scottclowe/python-ci,scottclowe/python-ci