[CNG] Upgrade s3cmd package to version 2.2.0

A new version (v2.2.0) of the s3cmd package was released on Sept. 26. Of the changes, the following is useful

• Added support for STS webidentity authentication (ie AssumeRole and AssumeRoleWithWebIdentity)

This new version will complete the IAM roles for service accounts (IRSA) support that was started in #1832 (closed) and #2710 (closed). Specifically it should allow the backups to use IRSA to store the backup in an AWS S3 bucket.

From my read of the backup job in the chart, there does not look like there is any need to change the chart to support this. Other than maybe a quick document update to note that if IRSA is being used the secret pointed to by gitlab.task-runner.backups.objectStorage.secret will not need to have access_key or secret_key specified.