STSAssumeRoleSessionCredentialsProvider is deprecated

The standard convention of using cross-account credentials seems to be to set `AWSCredentialsProvider` to `AWSCredentialsProvider = STSAssumeRoleSessionCredentialsProvider||` in the `samples.properties` config file.

However, [`STSAssumeRoleSessionCredentialsProvider`](https://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/com/amazonaws/auth/STSAssumeRoleSessionCredentialsProvider.html#STSAssumeRoleSessionCredentialsProvider-java.lang.String-java.lang.String-) seems to be deprecated and the new [`STSAssumeRoleSessionCredentialsProvider.Builder`](https://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/com/amazonaws/auth/STSAssumeRoleSessionCredentialsProvider.Builder.html) doesn't seem to work due to the fact it needs to build after-the-fact. This may require changes in the underlying multilang daemon.

There is also a related PR to add assume role support, however it doesn't address the deprecated functionality issue: https://github.com/awslabs/amazon-kinesis-client-python/pull/70