Migrate to crew 1.0.0

crew.aws.batch 0.0.8

• Deprecate retryable options because crew 1.0.0 no longer supports them.
• In the monitor, return POSIXct time stamps for created, started, stopped, timestamp and ingestion_time.
• Print log messages from log() with writeLines().
• When statusReason cannot be shown, show an informative text entry instead of NA.