Add link to reference of Kafka usage (#766)
Add link to reference of Kafka usage (#766)

This PR adds a link to the excellent blog:
`Streaming Machine Learning with Tiered Storage and Without a Data Lake`,
courtesy to Kai.

Signed-off-by: Yong Tang <765086fe2e0c1f980161f127fec596800f327f62@outlook.com>
tensorflow/io,tensorflow/io,tensorflow/io,tensorflow/io,tensorflow/io,tensorflow/io,tensorflow/io