Make sequence token optional

[gdziwoki]

Problem

https://aws.amazon.com/about-aws/whats-new/2023/01/amazon-cloudwatch-logs-log-stream-transaction-quota-sequencetoken-requirement/

Sequence tokens are no longer required. Would be nice to have a switch to make them optional and get rid of those pesky InvalidSequenceTokenException.

[petergvizd]

Looks like InvalidSequenceTokenException should not appear anymore according to https://docs.aws.amazon.com/AmazonCloudWatchLogs/latest/APIReference/API_PutLogEvents.html .
But anyway there is prepared PR for getting rid of it in code #251