Update the requirements to match global-requirements for dogpile.cache
Update the requirements to match global-requirements for dogpile.cache

For some reason this is resulting in a version conflict with
openstacksdk in some situations. Updating to match global-requirements
should resolve it.

Change-Id: I3a9af8b738da8ebf0c1f4cf632984bc4a0875d90
Related-Bug: #1809232

openstack/oslo.cache,openstack/oslo.cache