Split deploying to prod and staging (#666)

<!-- Provide a brief summary of your changes -->

## Motivation and Context
<!-- Why is this change needed? What problem does it solve? -->
The following PR splits the workflows for deploying to prod and staging
easing the use of gitops flows for promotions.

## How Has This Been Tested?
<!-- Have you tested this in a real application? Which scenarios were
tested? -->

## Breaking Changes
<!-- Will users need to update their code or configurations? -->

## Types of changes
<!-- What types of changes does your code introduce? Put an `x` in all
the boxes that apply: -->
- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update

## Checklist
<!-- Go over all the following points, and put an `x` in all the boxes
that apply. -->
- [ ] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [ ] My code follows the repository's style guidelines
- [ ] New and existing tests pass locally
- [ ] I have added appropriate error handling
- [ ] I have added or updated documentation as needed

## Additional context
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-->

Signed-off-by: Radoslav Dimitrov <radoslav@stacklok.com>

.github/workflows/deploy-production.yml

@@ -0,0 +1,56 @@
+name: Deploy to Production
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - 'deploy/Pulumi.gcpProd.yaml'
+
+permissions:
+  contents: read
+
+env:
+  PULUMI_VERSION: "3.188.0"
+
+jobs:
+  deploy-production:
+    name: Deploy to Production
+    runs-on: ubuntu-latest
+    environment: production
+    concurrency:
+      group: deploy-production
+      cancel-in-progress: false
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8
+
+      - name: Setup Go
+        uses: actions/setup-go@44694675825211faa026b3c33043df3e48a5fa00
+        with:
+          go-version-file: 'go.mod'
+          cache: true
+
+      - name: Setup Pulumi
+        uses: pulumi/actions@d7ceb0215da5a14ec84f50b703365ddf0194a9c8
+        with:
+          pulumi-version: ${{ env.PULUMI_VERSION }}
+
+      - name: Authenticate to Google Cloud
+        uses: google-github-actions/auth@7c6bc770dae815cd3e89ee6cdf493a5fab2cc093
+        with:
+          credentials_json: ${{ secrets.GCP_PROD_SERVICE_ACCOUNT_KEY }}
+
+      - name: Setup Google Cloud SDK
+        uses: google-github-actions/setup-gcloud@aa5489c8933f4cc7a4f7d45035b3b1440c9c10db
+        with:
+          project_id: mcp-registry-prod
+          install_components: gke-gcloud-auth-plugin
+
+      - name: Deploy to Production
+        working-directory: ./deploy
+        env:
+          PULUMI_PROD_PASSPHRASE: ${{ secrets.PULUMI_PROD_PASSPHRASE }}
+        run: |
+          echo "$PULUMI_PROD_PASSPHRASE" > passphrase.prod.txt
+          make prod-up