Release v0.1.21

What's Changed

• fix(bucket-encryption): allow default SSE-KMS key by @overtrue in #222
• feat(phase-2): refine sql select options by @GatewayJ in #217
• test(s3): cover JSON select output delimiter by @overtrue in #223
• feat(admin): show node and disk details in cluster info by @overtrue in #226

Full Changelog: v0.1.20...v0.1.21