Missing dependencies

Attempting to run the code fragment below (based on [this AWS example](https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/data-api.html#data-api.java-client-library)) reveals missing dependencies.

````
RdsDataClient client = RdsDataClient.builder().database(Database)
.resourceArn(Database_Resource_ARN)
.secretArn(Database_Secret_ARN).build();
client.forSql("select * from accounts").execute().mapToSingle(File.class);
````

Error message:

````
Exception in thread "main" java.lang.NoClassDefFoundError: com/google/common/base/Strings
at com.amazon.rdsdata.client.RdsDataClient.forSql(RdsDataClient.java:97)
at data1.main(data1.java:15)
Caused by: java.lang.ClassNotFoundException: com.google.common.base.Strings
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 2 more
````

Start by reproducing the example from data1.main and inspect the dependency usage reported at RdsDataClient.java:97. Check how the client library declares or packages its dependencies; done means the example runs without the NoClassDefFoundError for com.google.common.base.Strings.

索引モデルが issue の本文から書いたものです。