fix(docs): runnable example sample (#3575)

Co-authored-by: Patti Shin <[email protected]>

Author: rogerthatdev

CONTRIBUTING.md

@@ -17,9 +17,9 @@ Console](https://console.cloud.google.com/apis/library).
 
         gcloud auth application-default login
 
-1. Change directory to one of the sample folders, e.g. `datastore`.
+1. Change directory to one of the sample folders, e.g. `run/helloworld`.
 
-        cd datastore/
+        cd run/helloworld
 
 1. Install the dependencies.
 

README.md

@@ -40,9 +40,9 @@ visit the [Google Cloud Samples][cloud_samples] page.
 
 ## How to run a sample
 
-1. Change directory to one of the sample folders, e.g. `datastore`:
+1. Change directory to one of the sample folders, e.g. `run/helloworld`:
 
-        cd datastore/
+        cd run/helloworld
 
 1. Install the sample's dependencies (see the sample's README for details):