Create github workflow to deploy frontend to S3

* Ensure that action triggers only on push to main and on any changes to frontend directory
* Uploads contents in dist folder to s3 bucket

.github/workflows/frontend.yml

@@ -0,0 +1,40 @@
+name: Deploy Frontend
+
+on:
+  push:
+    branches: [ 'main' ]
+
+  workflow_dispatch:
+
+permissions:
+  id-token: write   # This is required for requesting the JWT
+  contents: read    # This is required for actions/checkout
+
+env:
+  AWS_REGION: ap-southeast-1
+  S3_BUCKET_NAME: app.peerprep.org
+
+jobs:
+  deploy:
+    name: Deploy Frontend
+    runs-on: ubuntu-latest
+    environment: production
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Configure AWS credentials
+        id: aws-configure
+        uses: aws-actions/configure-aws-credentials@v4.0.2
+        with:
+          role-to-assume: arn:aws:iam::491085383176:role/github_s3_copy
+          role-session-name: GitHub_to_AWS_via_FederatedOIDC
+          aws-region: ${{ env.AWS_REGION }}
+
+      - name: Build frontend distribution
+        working-directory: frontend
+        run: npm ci && npm run build
+
+      - name: Sync distribution to S3
+        run: |
+          aws s3 sync ./frontend/dist/frontend/browser/ s3://$S3_BUCKET_NAME --delete