pip install s3-credentials

% s3-credentials create my-new-s3-bucket --create-bucket
Created bucket:  my-new-s3-bucket
Created user: s3.read-write.my-new-s3-bucket with permissions boundary: arn:aws:iam::aws:policy/AmazonS3FullAccess
Attached policy s3.read-write.my-new-s3-bucket to user s3.read-write.my-new-s3-bucket
Created access key for user: s3.read-write.my-new-s3-bucket
{
    "UserName": "s3.read-write.my-new-s3-bucket",
    "AccessKeyId": "AKIAWXFXAIOZOYLZAEW5",
    "Status": "Active",
    "SecretAccessKey": "...",
    "CreateDate": "2021-11-03 01:38:24+00:00"
}