Comment 2 for bug 1719009

1 we need the script to generate the lower-constraints.txt ( https://review.openstack.org/518416 )
1.1 will take gr lower bounds and apply them as a constraint, overwriting the constraint listed in upper-constraints
2 use the generated lower-constraints.txt file and ensure that every package is individually available. via pypi json api.
2.1 We do not care about the co-installability of global lower-constraints.

Project needs a voting gate job that does the following.

1 generate a lower-requirements file from the projects requirements.txt.
1.1 it will convert >= values to === values
2 take that lower-requirements.txt file and install it
2.1 pip freeze and that becomes the lower-constraints.txt and is saved/updated.

Project needs a separate job that uses the lower-constraints.txt and runs the project's tests