Fix CI: add empty .merlin file to test root
Fix CI: add empty .merlin file to test root

rgrinberg/merlin,dra27/merlin,ocaml/merlin,dra27/merlin,dra27/merlin,ocaml/merlin,rgrinberg/merlin,rgrinberg/merlin,the-lambda-church/merlin,the-lambda-church/merlin,dra27/merlin,ocaml/merlin,the-lambda-church/merlin,rgrinberg/merlin,ocaml/merlin