feat: emit event on job lock extend failure

Created by: bewithjonam

Existing: When a job fails to extend its lock in redis, there is no way to debug or do find it out.

Change: When a job fails to extend its lock in redis, a new event lockExtendingFailed will be emitted.

Reason: In our use-case, each job processes data from a socket continuously and sends signals based on it when the jobs conditions are met. It is a long job(runs for days). We have multiple workers processing jobs. As already clearly mentioned in the Readme, if lock extension fails, it will lead to double processing of jobs.

Using this event, if extending lock fails, I will disconnect the socket so that it will stop duplicate processing.