gradle 2.1

Update gradle.rb

Closes #32155.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
Updating Tika to version 1.6

This just updates the Tika Formula to the newly-released 1.6 version of Apache Tika.
gradle: add 2.1 bottle.
tika: add 1.6 bottle.