Uppercase commands in CommandsParser.get_keys

[falk-h]

Pull Request check-list

• Does $ tox pass with this change (including linting)?
• Do the CI tests pass with this change (enable it first in your forked repo and wait for the github action build to finish)?
• Is the new or changed code fully tested?
• Is a documentation update included (if this change modifies existing APIs, or introduces new ones)?
• Is there an example added to the examples folder (if applicable)?
• Was the change added to CHANGES file?

I haven't been able to get tox to pass locally. I'm unsure what the problem is, but it seems like it's related to uvloop. I'm sure it's just a problem with my dev environment as everything passes in CI.

Description of change

I ran into issues when migrating from the blocking RedisCluster to asyncio.RedisCluster where asyncio.CommandsParser.get_keys would raise errors about commands not existing, even though everything worked with the blocking client. Passing the commands to asyncio.RedisCluster.execute_command as uppercase strings fixed the problem.

This change makes sure that commands passed to asyncio.CommandsParser.get_keys are always uppercased when used with the self.commands dict. This behavior is consistent with the blocking client. I thought that the commands maybe should be uppercased before being passed to get_keys but I haven't been able to find any code that looks like it does that. For reference, I was using commands from a proprietary Redis module.

[dvora-h]

@falk-h Nice catch, thank you!