Update doc

Author: philip-gai

docs/upgrade-node.md

@@ -7,6 +7,7 @@ This document describes how to upgrade the Node version used by the Announcement
 1. Update the node version in [package.json](/web-app/package.json)
 2. Update the nodesource link in [Dockerfile](/.devcontainer/Dockerfile)
 3. Update the `node-version` in [action.yml](/.github/workflows/composite/web-app-build-test/action.yml)
-4. Rebuild codespace
-5. Check `node -v`
-6. Continue [testing](./testing.md)
+4. Update the `linuxFxVersion` in [appservice-module.bicep](/infrastructure/modules/appservice-module.bicep)
+5. Rebuild codespace
+6. Check `node -v`
+7. Continue [testing](./testing.md)