ci: add upgrade guide generation step

Author: adrians5j

.github/workflows/create-release-branch.yml

@@ -39,6 +39,9 @@ jobs:
           CLAUDE_KEY: ${{ secrets.ANTHROPIC_API_KEY }}
         run: yarn generate:changelog --version ${{ inputs.version }}
 
+      - name: Generate upgrade guide
+        run: yarn generate:upgrade-guide --version ${{ inputs.version }}
+
       - name: Create branch, commit, and push
         run: |
           git config user.name "webiny-bot"