Create secrets as part of container app create/update

Hi,
I am using the action to deploy the containerapp.

My containerapp contains some environment variables which are sensitive. Hence I am relying on using containerapp secrets and referring the same in `environmentVariables`. The action I have currently is as follows:

```
- name: Build and deploy Container App
uses: azure/container-apps-deploy-action@v1
with:
acrName: ${{ env.ACR_NAME }}
acrUsername: ${{ secrets.ACR_CLIENT_ID }}
acrPassword: ${{ secrets.ACR_CLIENT_SECRET }}
imageToDeploy: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest
resourceGroup: ${{ env.RESOURCE_GROUP }}
containerAppEnvironment: ${{ env.CONTAINER_APP_ENV }}
containerAppName: ${{ env.CONTAINER_APP }}
ingress: external
targetPort: 5000
disableTelemetry: true
environmentVariables: "DATABASE_URL=secretref:db-url KEYCLOAK_CLIENT_SECRET=secretref:keycloak-client-secret"
```

It looks like this action will suceed only if the secret already exists. This means that this is more useful in update scenarios.

It would be very convenient if we could have created the secrets as part of the action and then use them within `environmentVariables`. Is this a possibility ?