docs: update the quickstart sample to use v1beta (#533)

* docs: update the quickstart sample to use v1beta

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

---------

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Author: ikuleshov

google-analytics-admin/src/main/java/com/example/analyticsadmin/QuickstartSample.java

@@ -44,16 +44,17 @@
 
 To run this sample using Maven:
   cd java-analytics-admin/samples/snippets
+  mvn install
   mvn exec:java -Dexec.mainClass="com.example.analytics.QuickstartSample"
 */
 
 // [START analytics_admin_quickstart]
 
-import com.google.analytics.admin.v1alpha.Account;
-import com.google.analytics.admin.v1alpha.AnalyticsAdminServiceClient;
-import com.google.analytics.admin.v1alpha.AnalyticsAdminServiceClient.ListAccountsPage;
-import com.google.analytics.admin.v1alpha.AnalyticsAdminServiceClient.ListAccountsPagedResponse;
-import com.google.analytics.admin.v1alpha.ListAccountsRequest;
+import com.google.analytics.admin.v1beta.Account;
+import com.google.analytics.admin.v1beta.AnalyticsAdminServiceClient;
+import com.google.analytics.admin.v1beta.AnalyticsAdminServiceClient.ListAccountsPage;
+import com.google.analytics.admin.v1beta.AnalyticsAdminServiceClient.ListAccountsPagedResponse;
+import com.google.analytics.admin.v1beta.ListAccountsRequest;
 
 public class QuickstartSample {