Fix github actions syntax

BUG=468386163
GWSQ_IGNORE: linjordan@google.com
PiperOrigin-RevId: 861363354
Change-Id: Ia80905c4947cd18febd4674065924cb6209c8df7

Author: jordanlin00

.github/workflows/docker-deploy.yaml

@@ -19,9 +19,9 @@ jobs:
       - id: 'auth'
         uses: 'google-github-actions/auth@v2'
         with:
-          workload_identity_provider: 'projects/{{ secrets.GCP_PROJECT_NUMBER }}/locations/global/workloadIdentityPools/github-pool/providers/github-provider'
-          service_account: '{{ secrets.SERVICE_ACCOUNT }}'
-          project_id: '{{ secrets.GCP_PROJECT_ID }}'
+          workload_identity_provider: 'projects/${{ secrets.GCP_PROJECT_NUMBER }}/locations/global/workloadIdentityPools/github-pool/providers/github-provider'
+          service_account: '${{ secrets.SERVICE_ACCOUNT }}'
+          project_id: '${{ secrets.GCP_PROJECT_ID }}'
 
       - name: 'Set up Cloud SDK'
         uses: 'google-github-actions/setup-gcloud@v2'