Add instructions on how to use prombench in readme (#148)
Add instructions on how to use prombench in readme (#148)

* Add instructions on how to trigger tests on github

Signed-off-by: Harsh Agarwal <4ecfb1cc1d90de38fb7c788e55cf4e56c37b971a@iith.ac.in>

prometheus/prombench,prometheus/prombench,prometheus/prombench