kagkarlsson/db-scheduler 8.0 on GitHub

PR #136 introduces a new feature where changes to the Schedule for
a RecurringTask is detected by the Scheduler on startup. Any existing execution is rescheduled to the new next execution-time
according to the new Schedule.
Note: A Schedule must now indicate whether it is deterministic or not (i.e. if it will evaluate to the same instants).
PR #134 fixes some edge-cases (that were fairly likely for
high-throughput cases) that caused the Scheduler to stop fetching further batches of due executions until next pollInterval.
PR #132 fixes race-condition for immediate-execution that may cause
the execution to be "missed" until next pollingInterval.
PR #131 upgrades guava to 29.0.
PR #129 adjusts defaults for Spring Boot to match SchedulerBuilder.
Contributions by evenh.