Add changelog for 4.2 release (#1299)
Add changelog for 4.2 release (#1299)


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