Update build.yml

Author: LiamConnors

.github/workflows/build.yml

@@ -101,3 +101,32 @@ jobs:
         with:
           name: site-build
           path: _site/
+
+      - name: Create GitHub App token
+        if: github.ref_name == 'update-ci' && github.repository == 'plotly/graphing-library-docs'
+        uses: actions/create-github-app-token@v2
+        id: app-token
+        with:
+          app-id: ${{ vars.DE_CI_GHAPP_ID }}
+          private-key: ${{ secrets.DE_CI_GHAPP_PRIVATE_KEY }}
+          owner: ${{ github.repository_owner }}
+
+      - name: Checkout documentation repo
+        if: github.ref_name == 'update-ci' && github.repository == 'plotly/graphing-library-docs'
+        uses: actions/checkout@v4
+        with:
+          repository: plotly/documentation
+          ref: test-pages
+          token: ${{ steps.app-token.outputs.token }}
+          path: documentation
+
+      - name: Deploy to test branch
+        if: github.ref_name == 'update-ci' && github.repository == 'plotly/graphing-library-docs'
+        run: |
+          git config --global user.email "accounts@plot.ly"
+          git config --global user.name "plotlydocbot"
+          cp -r _site/* documentation/
+          cd documentation
+          git add .
+          git commit -m "deploying https://github.com/plotly/graphing-library-docs/commit/${{ github.sha }}" || echo "No changes to commit"
+          git push