Fix build error due to scala bug #11125 (#967)

JDK 11 `java.lang.String#lines` conflicts with Scala `StringOps#lines`.
This has been fixed in scalac 2.12.8 but projects using 2.11 in their
cross-build need the `Predef.augmentString` patch.

[Scala bug & fix reference](https://github.com/scala/bug/issues/11125)