Fix issue with organization.metadata field not getting set to empty

[sergiught]

Description

Fixes: #236

Checklist

Note: Checklist required to be completed before a PR is considered to be reviewable.

Auth0 Code of Conduct

• I have read and agreed to the terms within the Auth0 Code of Conduct

Auth0 General Contribution Guidelines

• I have read the Auth0 General Contribution Guidelines

Changes include test coverage?

• Yes
• Not needed

Does the description provide the correct amount of context?

• Yes, the description provides enough context for the reviewer to understand what these changes accomplish

Have you updated the documentation?

• Yes, I've updated the appropriate docs
• Not needed

Is this code ready for production?

• Yes, all code changes are intentional and no debugging calls are left over

[codecov-commenter]

Codecov Report

Merging #245 (8c464f1) into patch/fix-issue65-with-org-update (6f32c87) will increase coverage by 0.00%.
The diff coverage is 42.85%.

@@                        Coverage Diff                         @@
##           patch/fix-issue65-with-org-update     #245   +/-   ##
==================================================================
  Coverage                              83.27%   83.27%           
==================================================================
  Files                                     36       36           
  Lines                                   6833     6835    +2     
==================================================================
+ Hits                                    5690     5692    +2     
  Misses                                   910      910           
  Partials                                 233      233           

Impacted Files	Coverage Δ
auth0/resource_auth0_organization.go	76.76% <42.85%> (+0.23%)	⬆️

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