Support retry backoff in Zeebe 1.3

[jwulf]

Zeebe 1.3 will support backoff retry for failed tasks. See here: camunda/camunda#5629.

The complete.fail() method of the job worker callback will probably need extending with an optional backoff time parameter.

[jwulf]

Here are the gRPC API changes (not merged yet in Dec 2021): https://github.com/camunda-cloud/zeebe/pull/8359/files

[jwulf]

From version 8.0.0 of the package, used with a 8.0.0 Zeebe broker, you can specify to the broker an optional backoff for the reactivation of the job, like this:

job.fail({errorMessage: 'Triggering a retry with a two second back-off', retryBackOff: 2000, retries: 1})