Add australiaeast to allowed locations for OpenAI (#259)

## Purpose
To add `australiaeast` to allowed locations for OpenAI - this is now
generally available according to
https://azure.microsoft.com/en-us/explore/global-infrastructure/products-by-region/?products=cognitive-services&regions=australia-central,australia-central-2,australia-east,australia-southeast

## Does this introduce a breaking change?
<!-- Mark one with an "x". -->
```
[ ] Yes
[x] No
```

## Pull Request Type
<!-- Please check the one that applies to this PR using "x". -->
```
[ ] Bugfix
[x] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Documentation content changes
[ ] Other... Please describe:
```

## How to Test
Run `azd up` and choose `australiaeast`

Author: amul047

infra/main.bicep

@@ -11,7 +11,7 @@ param location string
 param tags string = ''
 
 @description('Location for the OpenAI resource group')
-@allowed([ 'canadaeast', 'eastus', 'eastus2', 'francecentral', 'switzerlandnorth', 'uksouth', 'japaneast', 'northcentralus' ])
+@allowed([ 'canadaeast', 'eastus', 'eastus2', 'francecentral', 'switzerlandnorth', 'uksouth', 'japaneast', 'northcentralus', 'australiaeast' ])
 @metadata({
   azd: {
     type: 'location'