Update integrations endpoint to v3

[ckeif-duo]

This updates the only reference to /admin/v1/integrations to /admin/v3/integrations similar to duosecurity/duo_client_python#282. It also includes changes to update to canonicalization v5.

Description

Updates the /admin/v1/integrations reference to v3.

Because the v3 endpoints require canonicalization 5, the larger change in this PR is updating the canonicalization to 5.

Motivation and Context

The v3 integrations endpoints add a new user_access field and change the behavior of the groups_allowed field.

Previously the groups_allowed field by itself determined which users could authenticate with the application as described here. Now a third state has been added which allows no users to authenticate.

Because of that, the user_access field has been added to express this more cleanly, and groups_allowed can only be provided if user_access == "PERMITTED_GROUPS".

How Has This Been Tested?

• Verified admin/v3/integrations endpoint is working as expected
• Regression tested some old V1 endpoints (POST admin/v1/groups, POST admin/v1/groups/:gkey, POST admin/v1/users

https://gist.github.com/ckeif-duo/f86490d5380f6c57bfde4031e02e6795

Types of Changes

• 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 change)