MinIO: Minor Bug Fix Release

## Highlights - **Breaking change** Prometheus endpoint now requires to be authorized with a bearer token. See (#7640) and https://github.com/minio/cookbook/blob/master/docs/how-to-monitor-minio-with-prometheus.md for further details. - Improvements and code clean up related to SSE validation. See (#8276, #8259, #8278 and #8267) for more details. ## Changelog - Fix writing 'format.json' and make it atomic (#8296) (09/24/19) - Update minio-go to latest release (#8297) (09/24/19) - s3: Encode continuation & next continuation tokens when asked (#8292) (09/24/19) - Fix LDAP responseXML to be named appropriately (#8285) (09/24/19) - Add checks in DiskInfo() to protect against changing mounts (#8286) (09/23/19) - remove SSE-S3 key rotation in CopyObject (#8278) (09/24/19) - Cleanup ResponseWriter function for audit and trace (#8283) (09/24/19) - fix link to let's encrypt doc (#8294) (09/23/19) - Add metrics healthcheck test with JWT (#8287) (09/22/19) - starts-with policy condition support issue (#7937) (09/22/19) - Fix all failing tests with -race (09/22/19) - Authorize prometheus endpoint with bearer token (#7640) (09/22/19) - log server startup messages to admin console api (#8264) (09/22/19) - make the crypto error type a native go type (#8267) (09/22/19) - Add a basic .dockerignore file to reduce docker context in `make docker` (#8282) (09/21/19) - make SSE request header check comprehensive (#8276) (09/21/19) - Remove setting net.Conn Deadlines as its not needed anymore (#8269) (09/20/19) - S3 select: flush when reaching limit (#8279) (09/20/19) - remove the unused code for decrypting `io.Writer` (#8277) (09/20/19) - remove TLS 1.3 opt-in code (#8275) (09/20/19) - Check for connection errors during event transit in elasticsearch and webhook (#8273) (09/19/19) - fix get container id bug (#8196) (09/19/19) - prepare SSE-S3 metadata parsing for K/V data key store (#8259) (09/19/19)