Use `FieldMask` to update resource

[huan]

Current we have contactAlias() method to update alias.

It seems that we can use contactUpdate() with FieldMask to do the update, and it will support update all properties in the payload.

See:

• https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#fieldmask
• https://pinkiepractices.com/posts/protobuf-field-masks/