Add audience specification in GHA workflow

Author: dpowley

.github/workflows/go-getter.yml

@@ -75,6 +75,7 @@ jobs:
         with:
           workload_identity_provider: 'projects/328212837253/locations/global/workloadIdentityPools/hc-go-getter-test/providers/hc-go-getter-test'
           service_account: hc-go-getter-test@hc-e56c0f7c21c448d2be9e7696073.iam.gserviceaccount.com
+          audience: https://github.com/hashicorp
 
       - name: Run go tests
         run: |
@@ -147,6 +148,7 @@ jobs:
         with:
           workload_identity_provider: 'projects/328212837253/locations/global/workloadIdentityPools/hc-go-getter-test/providers/hc-go-getter-test'
           service_account: hc-go-getter-test@hc-e56c0f7c21c448d2be9e7696073.iam.gserviceaccount.com
+          audience: https://github.com/hashicorp
 
       - name: Run go tests
         shell: bash