Temporary Hack to make it seem that there is still a dev 1.6.0 Retriever

[edeutsch]

Since the TRAPI 1.6.0 dev version of Retriever is now gone and no longer registered in SmaryAPI, if we want TRAPI 1.6.0 versions of ARAX dev to keep working (I think we do), then we need to remap a working 1.6.0 of Retriever into dev.

[edeutsch]

Close this issue when the above committed code is removed from the codebase