MINOR: Make link in quickstart dynamic
Reviewer: Matthias J. Sax
</h4>
<p>
- <a href="https://www.apache.org/dyn/closer.cgi?path=/kafka/3.1.0/kafka_2.13-3.1.0.tgz">Download</a>
+ <a href="https://www.apache.org/dyn/closer.cgi?path=/kafka/{{fullDotVersion}}/kafka_{{scalaVersion}}-{{fullDotVersion}}.tgz">Download</a>
the latest Kafka release and extract it:
</p>
