Update continuous-integration-delivery-improvements.md

@microsoft/azure-data-factory-utilities requires node 18.x. Updating node version in documentation, and the task used to install node, to the latest version.

Author: joe-plumb

articles/data-factory/continuous-integration-delivery-improvements.md

@@ -145,9 +145,9 @@ Follow these steps to get started:
 
    # Installs Node and the npm packages saved in your package.json file in the build
 
-   - task: NodeTool@0
+   - task: UseNode@1
      inputs:
-       versionSpec: '14.x'
+       version: '18.x'
      displayName: 'Install Node.js'
 
    - task: Npm@1