Ensure CSV OCP version range includes OCP 4.8 if tested

At the moment we have only tested against the available versions which include up to OCP 4.7. With 4.8 recently released we also need to test against that, however there are ongoing problems in getting a working OCP 4.8 cluster to utilize for testing that need to be resolved first.

Assuming the issues get resolve and 7.9 is tested against 4.8, we will need to update the label of the valid openshift range.