Bump minimal dune version

Author: Leonidas-from-XIV

packages/yojson/yojson.2.0.2/opam

@@ -14,7 +14,7 @@ build: [
 ]
 depends: [
   "ocaml" {>= "4.02.3"}
-  "dune"
+  "dune" {>= "2.0"}
   "cppo" {build}
   "alcotest" {with-test & >= "0.8.5"}
   "odoc" {with-doc}