Update template CD to use Platform CLI (#768)

Update template CD to:
- Keep lorenyu/platform-cli branch up to date with main
- Install nava-platform CLI
- Use nava-platform CLI to update platform-test repos

## Context

As part of migrating to use the Platform CLI we are going to first get
the platform-test* repos to start updating using the Platform CLI

.github/workflows/template-only-cd.yml

@@ -10,9 +10,27 @@ on:
 concurrency: platform-template-only-cd
 
 jobs:
+  # TODO: Get rid of this job once we've merged the platform-cli branch into the main branch
+  update-platform-cli-branch:
+    name: Update platform-cli branch
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout template-infra repo
+        uses: actions/checkout@v4
+        with:
+          path: template-infra
+          ref: lorenyu/platform-cli
+          # Fetch history of all branches so we can merge main into the feature branch
+          fetch-depth: 0
+      - name: Update
+        working-directory: template-infra
+        run: |
+          git merge origin/main
+          git push
   deploy:
     name: Deploy to ${{ matrix.project_repo }}
     runs-on: ubuntu-latest
+    needs: update-platform-cli-branch
     strategy:
       fail-fast: true
       matrix:
@@ -25,23 +43,36 @@ jobs:
         uses: actions/checkout@v4
         with:
           path: template-infra
+          # TODO: Revert to checking out main once we've merged the platform-cli branch into the main branch
+          ref: lorenyu/platform-cli
+          # Fetch history because the Platform CLI needs it to do the update
+          fetch-depth: 0
       - name: Checkout project repo
         uses: actions/checkout@v4
         with:
           path: project-repo
           repository: ${{ matrix.project_repo }}
           token: ${{ secrets.PLATFORM_BOT_GITHUB_TOKEN }}
 
-      - name: Update infra template
-        working-directory: project-repo
-        run: ../template-infra/template-only-bin/update-template
+      # Set up Python since built in Python version (3.10.12) is not supported by Platform CLI (<4.0,>=3.11)
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.13'
 
-      - name: Push changes to project repo
+      - name: Install nava-platform CLI
+        run: pipx install --python python3.13 git+https://github.com/navapbc/platform-cli
+
+      - name: Configure git
         working-directory: project-repo
         run: |
           git config user.name nava-platform-bot
           git config user.email platform-admins@navapbc.com
-          git add --all
-          # Commit changes (if no changes then no-op)
-          git diff-index --quiet HEAD || git commit -m "Template infra deploy #${{ github.run_id }}"
-          git push
+
+      - name: Update infra template
+        working-directory: project-repo
+        run: nava-platform infra update --template-uri ../template-infra --version lorenyu/platform-cli .
+
+      - name: Push changes to project repo
+        working-directory: project-repo
+        run: git push