v1.15.1

Breaking changes:

• Rename ycsb workloadd to workloadx to show that it is a custom PKB
  write-only workload.

New features:

• Add FairSeq Roberta Masked Multilingual LM benchmark for linux.
• Add bulk delete API operation to object storage API scripts.
• Catch preemptible instance's interrupt event.

Enhancements:

• Enable support for AWS's c6g and r6g families.
• Integrate edw_benchmark with new Client Interface and results aggregation
  framework.
• Update default stress-ng version from 5.23 to 9.25 (default on Ubuntu 1804).
• Added two new workloads(workloadw and workloadw_uniform) for testing mostly
  write use cases(read/write 5/95)

Bug fixes and maintenance updates:

• Parallelize entity deletion processing for a kind.
• Move coremark installation into a package.
• Fixed one object per stream run for object storage service benchmark.
• Benchmarking of AWS Athena now records client observed run time rather that
  Athena's reported run time.
• Use sub processes instead of threads for entity deletion processing.