use pekko instead of akka?

[pjfanning]

• s3mock uses an old version of akka-http so you are not really affected by the akka license change
• unfortunately, all open source releases of akka-http are affected by security issues
• Apache Pekko is an open source fork of Akka (and includes pekko-http). Pekko has no known security issues and will fix any that get reported to us.
  • it's pretty easy to switch from akka-http to pekko-http - see https://pekko.apache.org/docs/pekko-http/current/release-notes/index.html
• relates to It's time to fix the build and upgrade libraries #184

[marko-asplund]

Just created PR #190 for migrating to pekko.
The code compiles, but I'm seeing lots of test failures.

@pjfanning Have you found a replacement for this?
If not, help would be welcome 😄