Semantic versioning of com.google.inject.multibindings package is violated because of API break in Guice 4.0.

In the 4.0 release the MultiBindingsTargetVisitor interface has been extended with an additional 'visit(OptionalBinderBinding optional binding)' method. This is an API break, as all implementers of the 3.0 version are now no longer compatible. The com.google.inject.multibindings package however still indicates compatibility by exporting version 1.4 instead of 2.0.