Add GHA workflow for submitting tags to metric service.

Author: yifanyang

.github/workflows/health-metrics-test.yml renamed to .github/workflows/health-metrics-presubmit.yml

@@ -3,6 +3,10 @@ name: Health Metrics
 on: [push, pull_request]
 
 env:
+<<<<<<< HEAD:.github/workflows/health-metrics-test.yml
+=======
+  METRICS_SERVICE_URL: "https://api.firebase-sdk-health-metrics.com"
+>>>>>>> 7b37f3376 (Add GHA workflow for submitting tags to metric service.):.github/workflows/health-metrics-presubmit.yml
   GITHUB_PULL_REQUEST_NUMBER: ${{ github.event.pull_request.number }}
   # TODO(yifany): parse from git commit history directly
   #   Reason: actions/checkout@v2 does not always honor ${{ github.event.pull_request.base.sha }},

.github/workflows/health-metrics-release.yml

@@ -0,0 +1,19 @@
+name: Health Metrics
+
+on:
+  push:
+    tags: ['**']
+
+jobs:
+  release-diffing:
+    name: Release Diffing
+    runs-on: ubuntu-latest
+    steps:
+      - uses: google-github-actions/setup-gcloud@master
+        with:
+          service_account_key: ${{ secrets.GCP_SA_KEY }}
+      - uses: yifanyang/github-actions/health-metrics/release-diffing@master
+        with:
+          repo: ${{ github.repository }}
+          ref: ${{ github.ref }}
+          commit: ${{ github.sha }}