Dependency update & dont pin confluent kafka to <= 2
We found on the dev call this morning that we're using an outdated version of igwn-alert, despite having updated dependencies since the 0.3.*
versions came out. I tracked this down to constraining confluent kafka to use at least 1.9.2 but <= 2.*. This MR removes the confluent-kafka < 2.*
constraint and updates the dependencies.