Add a message in 'Get Started Page' (kubeflow#3152)

* Add a message in 'Get Started Page'

* remove extra empty line

* attempt to fix test

* update snapshot

frontend/src/pages/GettingStarted.tsx

@@ -50,7 +50,7 @@ const PAGE_CONTENT_MD = ({
 
 ## Build your own pipeline
 
-Build an end-to-end ML pipeline with TensorFlow Extended (TFX) [**Start Here!**](https://console.cloud.google.com/mlengine/notebooks/deploy-notebook?q=download_url%3Dhttps%253A%252F%252Fraw.githubusercontent.com%252Ftensorflow%252Ftfx%252Fmaster%252Fdocs%252Ftutorials%252Ftfx%252Ftemplate.ipynb)
+Build an end-to-end ML pipeline with TensorFlow Extended (TFX) [**Start Here!**](https://console.cloud.google.com/mlengine/notebooks/deploy-notebook?q=download_url%3Dhttps%253A%252F%252Fraw.githubusercontent.com%252Ftensorflow%252Ftfx%252Fmaster%252Fdocs%252Ftutorials%252Ftfx%252Ftemplate.ipynb) (Please make sure you pick a Tensorflow 2.1 notebook instance.)
 
 <br/>
 

frontend/src/pages/__snapshots__/GettingStarted.test.tsx.snap

@@ -5,7 +5,7 @@ exports[`GettingStarted page fallbacks to show pipeline list page if request fai
 - First value
 + Second value
 
-@@ -69,11 +69,13 @@
+@@ -70,11 +70,13 @@
               >
             </li>
           </ul>
@@ -46,6 +46,7 @@ exports[`GettingStarted page initially renders documentation 1`] = `
             Start Here!
           </strong>
         </a>
+         (Please make sure you pick a Tensorflow 2.1 notebook instance.)
       </p>
       <br />
       <h2
@@ -259,7 +260,7 @@ exports[`GettingStarted page renders documentation with pipeline deep link after
 - First value
 + Second value
 
-@@ -16,11 +16,13 @@
+@@ -17,11 +17,13 @@
       <h2 id=\\"demonstrations-and-tutorials\\">Demonstrations and Tutorials</h2>
       <p>This section contains demo and tutorial pipelines.</p>
       <p><strong>Demos</strong> - Try an end-to-end demonstration pipeline.</p>
@@ -274,7 +275,7 @@ exports[`GettingStarted page renders documentation with pipeline deep link after
               Classification pipeline with model analysis, based on a public
               BigQuery dataset of taxicab trips.
               <a
-@@ -32,11 +34,13 @@
+@@ -33,11 +35,13 @@
               >
             </li>
           </ul>
@@ -289,7 +290,7 @@ exports[`GettingStarted page renders documentation with pipeline deep link after
               An example of end-to-end distributed training for an XGBoost model.
               <a
                 href=\\"https://github.com/kubeflow/pipelines/tree/master/samples/core/xgboost_training_cm\\"
-@@ -54,11 +58,13 @@
+@@ -55,11 +59,13 @@
         <strong>Tutorials</strong> - Learn pipeline concepts by following a
         tutorial.
       </p>
@@ -304,7 +305,7 @@ exports[`GettingStarted page renders documentation with pipeline deep link after
               Shows how to pass data between python components.
               <a
                 href=\\"https://github.com/kubeflow/pipelines/tree/master/samples/tutorials/Data%20passing%20in%20python%20components\\"
-@@ -69,11 +75,13 @@
+@@ -70,11 +76,13 @@
               >
             </li>
           </ul>