Remove the upper bound on tenacity version
Unfortunately tenacity doesn't maintain a changelog, but there don't seem to be any incompatible changes since the last 5.x release: https://github.com/jd/tenacity/compare/5.1.5...master
Unfortunately tenacity doesn't maintain a changelog, but there don't seem to be any incompatible changes since the last 5.x release: https://github.com/jd/tenacity/compare/5.1.5...master