Update GovernanceAssignment.yml

[myatt83]

fix typo

[learn-build-service-prod[bot]]

Learn Build status updates of commit c9c87c8:

:white_check_mark: Validation status: passed

File	Status	Preview URL	Details
preview-packages/docs-ref-autogen/@azure/arm-security/GovernanceAssignment.yml	:white_check_mark:Succeeded	View (azure-node-preview)

For more details, please refer to the build report.

For any questions, please:

• Try searching the learn.microsoft.com contributor guides
• Post your question in the Learn support channel