Update UnsupportedServer check

[danielnolan]

• We are getting errors from redis like ERR unknown command 'HELLO' reported from the redis-client gem after updating our app to Sidekiq 7. After looking into the redis_client source code it looks like we test for that message to raise a more helpful UnsupportedServer error, but the string being tested for inlcludes back quotes where the error coming from the redis server includes single quotes
• Replace includes? with match? so we can use a regex to match the string with single or back quotes to raise the UnsupportedServer error.
• Update the UnsupportedServer error message to say that the server needs to be Redis 6+ with the HELLO command available since sometimes commands can be unavailable even in supported Redis versions

[mperham]

Redis Labs informed me that they don't expect RESP3 support before July 2023.

https://github.com/mperham/sidekiq/blob/main/docs/7.0-Upgrade.md#known-issues

[casperisfine]

Thanks @danielnolan. I merged a very sligthly modified version.