#49 Send Message Update
In Send Message API, only merchant can use amount parameter. Added a parameter user to specify if the use is a merchant
#50 Strict values for some previously nullable values
Disallowed null some parameters where the corresponding endpoints required values
#51 Fixed wrong timezone
Fixed wrong timezone for expiresAt parameter when creating check. Request.fomatter is now deprecated and no need to use it as a workaround.
#52 Primitive values as parameters
Changed wrapper parameters (e.g. Integer, Double, etc.) to primitive types (e.g. int, double) to handle null values explicitly