Update Readme.md on expected behaviour if user sends duplicated entities in authz request

[camarcio]

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Bug Category

Policy evaluation

Describe the bug

Update the Readme section simple::Authorizer is_authorized API Semantics with new behaviour of Cedar v3 when evaluating authz requests with duplicated entities.

Duplicated entities in this context refers to users, resources, etc that are both present in the entities provider and request entities.

Important: update code snippets in Readme.md

Expected behavior

Readme section updated that we don't accept requests with duplicated entities.

Reproduction steps

N/A

Code Snippet

// Put your code below this line.

Log output

// Put your output below this line

Additional configuration

No response

Operating System

No response

Additional information and screenshots

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