Add custom header to requests

[lukeflo]

Hi,

I like your CLI since it seems to be like mc with better UI etc.

However, since I work with some custom self-hosted S3 storage systems, I need to pass custom amz headers to some S3 requests. Therefore, it would be great if a global flag would be available which allows to set those headers. Very much like its possible with mc or curl:

# mc
mc mb account/bucket -H "x-amz-bucket-encrypt-enabled:1"

# curl
curl --user '<ACCESS-KEY>:<SECRET-KEY>' \
  --aws-sigv4 "aws:amz:auto:s3" \
  "https://<BUCKET-NAME>.xyz.storage.org" \
  -X PUT \
  -H "x-amz-bucket-encrypt-enabled: 1"

If such a feature already exists, I haven't found it in the help pages so far.