[DXCDT-175] Add read and update to Duo Settings

[sergiught]

Description

This PR adds support to update settings on Duo, needed for auth0/terraform-provider-auth0#165.

References

Testing

• This change adds test coverage for new/changed/fixed functionality

Checklist

• I have read and agreed to the terms within the Auth0 Code of Conduct.
• I have read the Auth0 General Contribution Guidelines.
• I have reviewed my own code beforehand.
• I have added documentation for new/changed functionality in this PR.
• All active GitHub checks for tests, formatting, and security are passing.
• The correct base branch is being used, if not main.

[codecov-commenter]

Codecov Report

Merging #84 (8b11307) into feature/DXCDT-175-guardian++-part1 (b5ac609) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@                          Coverage Diff                           @@
##           feature/DXCDT-175-guardian++-part1      #84      +/-   ##
======================================================================
+ Coverage                               94.62%   94.64%   +0.02%     
======================================================================
  Files                                      33       33              
  Lines                                    5582     5604      +22     
======================================================================
+ Hits                                     5282     5304      +22     
  Misses                                    240      240              
  Partials                                   60       60              

Impacted Files	Coverage Δ
management/guardian.go	92.43% <100.00%> (+0.33%)	⬆️
management/management.gen.go	100.00% <100.00%> (ø)

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