Test instrumented Scala HTTP client and server libraries for HTTP/2 support.

[jtduffy]

Issue #2064 cataloged all Java and Scala HTTP client and server frameworks that the agent instruments. All the Java based libraries were tested. This issue is for testing the Scala specific libraries.

• Does the library itself support HTTP/2
• If yes, does our instrumentation properly report up transactions when using HTTP/2

Results can be recorded here:
https://docs.google.com/spreadsheets/d/150ntwH2aO9Sr6mg0lVVkNScmLKSJpxNZXhqAoTHKo5U/edit?usp=sharing

[workato-integration]

https://new-relic.atlassian.net/browse/NR-330512