Bump Finagle and Finatra versions (#6843)

- Finagle to 21.9.0
- Finatra to 21.9.0

frameworks/Scala/finagle/build.sbt

@@ -1,4 +1,4 @@
-lazy val finagleVersion = "21.8.0"
+lazy val finagleVersion = "21.9.0"
 
 name := "finagle-benchmark"
 scalaVersion := "2.12.12"

frameworks/Scala/finatra/build.sbt

@@ -1,4 +1,4 @@
-lazy val finatraVersion = "21.8.0"
+lazy val finatraVersion = "21.9.0"
 
 name := "techempower-benchmarks-finatra"
 organization := "com.twitter"