Update Scala and Akka dep version to latest

[chetanmeh]

Update to latest Akka and Scala version as per it being used in incubator-openwhisk apache/openwhisk#4316

[codecov-io]

Codecov Report

Merging #49 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #49   +/-   ##
=======================================
  Coverage   95.31%   95.31%           
=======================================
  Files           6        6           
  Lines         128      128           
  Branches       14        8    -6     
=======================================
  Hits          122      122           
  Misses          6        6

Impacted Files	Coverage Δ
...adobe/api/platform/runtime/mesos/MesosClient.scala	0% <0%> (ø)	⬆️
...m/adobe/api/platform/runtime/mesos/TaskStore.scala	0% <0%> (ø)	⬆️

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