Update to lagom 1.5.5 about lagom-js

[mliarakos]

The basic process I go through for a new version of Lagom is:

• Update baseLagomVersion in build.sbt
• Review the commits for the new version of Lagom and check if any of the lagom.js specific source files need to be updated to reflect upstream Lagom changes
• Update the versions of sbt, plugins, and dependencies, keeping dependencies shared with Lagom at the same version as Lagom (e.g., play-json, scalatest)
• Run tests in sbt with: +test
• Check that the demo works with the new version, generally by using a locally published snapshot

If you're reusing a previous git repository, it's a good idea to run +clean and cleanLagomLibrary first.

[mliarakos]

Released 0.1.1-1.5.5.