WIP: Oracle Database 21.3 XE Test Action

[Michael-A-McMahon]

This is a work in progress. I'm creating the pull request in order to verify if the new test action is working correctly.

This branch adds a new action to the github workflow. It will create and run a docker image of Oracle Database 21.3 XE, and then verify Oracle R2DBC with this database.

This action will execute along side the existing test action for the 18.4 XE database.

[Michael-A-McMahon]

Finally got this working :)

[Michael-A-McMahon]

This pulls in changes from #68 Maybe want to review and merge that first

[Michael-A-McMahon]

Never mind. I checked the log and I see failed tests. I wonder why it shows a green check mark :(