ACR sku need to be Premium if policy "Public network access should be disabled for Container registries" applies

> Please provide us with the following information:
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### This issue is for a: (mark with an `x`)
```
- [ ] bug report -> please search issues before submitting
- [ ] feature request
- [x ] documentation issue or request
- [ ] regression (a behavior that used to work and stopped in a new release)
```

### Minimal steps to reproduce
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Deploy to subscription with this policy set "Public network access should be disabled for Container registries"

### Any log messages given by the failure
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"message": "{\r\n \"error\": {\r\n \"code\": \"DisablingPublicNetworkAccessNotSupported\",\r\n \"message\": \"Disabling public network access is not supported for the SKU Basic. For more information, please visit https://aka.ms/acr/private-link.\"\r\n },\r\n \"status\": \"Failed\"\r\n}",

### Expected/desired behavior
>

### OS and Version?
> Windows 7, 8 or 10. Linux (which distribution). macOS (Yosemite? El Capitan? Sierra?)

### Versions
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### Mention any other details that might be useful

Changing Basic to Premium in main.bicep line 8 seems like it will fix.
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