Update akka-actor, akka-stream to 2.6.20 (#2722)
Update akka-actor, akka-stream to 2.6.20 (#2722)

* Update akka-actor, akka-stream to 2.6.20

* Revert commit(s) 1b8596134

* Update akka-actor, akka-stream to 2.6.20
sksamuel/elastic4s,sksamuel/elastic4s