CLOUDP-141434: Add RootCertType to the atlas go client

[andreaangiolillo]

Description

The cluster struct is missing the RootCertType parameter. (API)

Link to any related issue(s):

Type of change:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Required Checklist:

• I have signed the MongoDB CLA
• I have added tests that prove my fix is effective or that my feature works
• I have added any necessary documentation (if appropriate)
• I have run make fmt and formatted my code

Further comments

[andreaangiolillo]

Looking at the codebase, RootCertType is an enum that can have the value ISRGROOTX1 and DST but while trying to create a cluster with RootCertType: DST I got the error:

{
  "detail" : "Cannot switch to use DST certificates in Atlas clusters.",
  "error" : 400,
  "errorCode" : "DST_ROOT_CERT_UNSUPPORTED",
  "parameters" : [ ],
  "reason" : "Bad Request"
}%

I am closing this PR since the only value allowed for RootCertType is ISRGROOTX1

[andreaangiolillo]

FYI: Reopened the PR since we still want to show the field when retrieved

[andreaangiolillo]

FYI: you cannot set RootCertType as ""

{
  "detail" : "An invalid enumeration value  was specified.",
  "error" : 400,
  "errorCode" : "INVALID_ENUM_VALUE",
  "parameters" : [ "" ],
  "reason" : "Bad Request"
}