Fix hdfs module dependencies in pulsar-io/docs module
*Motivation*
In pulsar-io-hdfs is changed to two modules `pulsar-io-hdfs2`
and `pulsar-io-hdfs3`. But the module is not updated in `pulsar-io/docs` module.
</dependency>
<dependency>
<groupId>${project.groupId}</groupId>
- <artifactId>pulsar-io-hdfs</artifactId>
+ <artifactId>pulsar-io-hdfs2</artifactId>
+ <version>${project.version}</version>
+ </dependency>
+ <dependency>
+ <groupId>${project.groupId}</groupId>
+ <artifactId>pulsar-io-hdfs3</artifactId>
<version>${project.version}</version>
</dependency>
<dependency>
