fix opam

Author: gares

elpi.opam

@@ -22,7 +22,7 @@ depends: [
   "re" {>= "1.7.2"}
   "ppx_deriving" {>= "4.3"}
   "ANSITerminal" {with-test}
-  "cmdliner" {with-test}
+  "cmdliner"  {with-test & < "2.0"}
   "fileutils" {with-test}
   "yojson" {with-test}
   "dune" {>= "2.9.0"}