Add S3 tags and update github description

[gurghet]

I noticed there are no S3 tags and the descriptions says "Standalone alternative to Kafka JDBC Connector"
I propose to update it to "Standalone alternative to Kafka JDBC Connector and S3 Kafka Connector"

[sirocchj]

Amended description and tags, left it more general as we intend provide more than just doobie and s3

[gurghet]

Awesome!