Sets the primary version of a symmetric key.
googlekms.setPrimaryVersion(keyName, versionId, [callback])
The 'callback' parameter specifies a function which will be called when the operation completes (or an error is encountered). If the 'callback' parameter is not specified, then the method will block and will not return until the operation completes (or an error is encountered).
The callback for this method is defined as:
'err' is the error that occurred. If there was no error, then 'err' is 'null'.
'err' has 2 properties which hold detailed information:
This method sets the primary version of the symmetric key specified by KeyName to the version identified by VersionId.
A symmetric key's primary version is the one used by the server when Encrypt is called. It can be changed at any time. Asymmetric keys cannot have primary versions.