post https://api.linode.com//managed/credentials//update
Updates the username and password for a Managed Credential.
This operation can only be accessed by the unrestricted users of an account.
linode-cli managed credential-update-username-password 9991 \
--username johndoe \
--password s3cur3P@ssw0rd
<https://www.linode.com/docs/products/tools/cli/get-started/>
account:read_write
<https://techdocs.akamai.com/linode-api/reference/get-started#oauth>