👷(CI) add deploy workflow

Add the deploy workflow, this workflow will deploy
the application to the selected tag.

.github/workflows/deploy.yml

@@ -0,0 +1,51 @@
+name: Deploy
+
+on:
+  push:
+    tags:
+      - 'preprod'
+
+
+jobs:
+  notify-argocd:
+    runs-on: ubuntu-latest
+    steps:
+      -
+        uses: actions/create-github-app-token@v1
+        id: app-token
+        with:
+          app-id: ${{ secrets.APP_ID }}
+          private-key: ${{ secrets.PRIVATE_KEY }}
+          owner: ${{ github.repository_owner }}
+          repositories: "people,secrets"
+      -
+        name: Checkout repository
+        uses: actions/checkout@v2
+        with:
+          submodules: recursive
+          token: ${{ steps.app-token.outputs.token }}
+      -
+        name: Load sops secrets
+        uses: rouja/actions-sops@main
+        with:
+          secret-file: secrets/numerique-gouv/people/secrets.enc.env
+          age-key: ${{ secrets.SOPS_PRIVATE }}
+      -
+        name: Call argocd github webhook
+        run: |
+          data='{"ref": "'$GITHUB_REF'","repository": {"html_url":"'$GITHUB_SERVER_URL'/'$GITHUB_REPOSITORY'"}}'
+          sig=$(echo -n ${data} | openssl dgst -sha1 -hmac ''${ARGOCD_WEBHOOK_SECRET}'' | awk '{print "X-Hub-Signature: sha1="$2}')
+          curl -X POST -H 'X-GitHub-Event:push' -H "Content-Type: application/json" -H "${sig}" --data "${data}" $ARGOCD_WEBHOOK_URL
+          sig=$(echo -n ${data} | openssl dgst -sha1 -hmac ''${ARGOCD_PRODUCTION_WEBHOOK_SECRET}'' | awk '{print "X-Hub-Signature: sha1="$2}')
+          curl -X POST -H 'X-GitHub-Event:push' -H "Content-Type: application/json" -H "${sig}" --data "${data}" $ARGOCD_PRODUCTION_WEBHOOK_URL
+
+  start-test-on-preprod:
+    needs:
+      - notify-argocd
+    runs-on: ubuntu-latest
+    if: startsWith(github.event.ref, 'refs/tags/preprod')
+    steps:
+      -
+        name: Debug
+        run: |
+          echo "Start test when preprod is ready"