Update named credential

PATCH {{_endpoint}}/services/data/v{{version}}/tooling/sobjects/NamedCredential/:NAMED_CREDENTIAL_ID

Request Body

{"FullName"=>"MyNamedCredential", "Metadata"=>{"label"=>"My Named Credential", "endpoint"=>"arn:aws:AWS_REGION:AWS_ACCOUNT_ID", "principalType"=>"Anonymous", "protocol"=>"NoAuthentication"}}