Fix version constraint

Author: smuenzel

packages/float_option/float_option.0.0.2/opam

@@ -9,7 +9,7 @@ homepage: "https://github.com/engineeredabstraction/float_option"
 bug-reports: "https://github.com/engineeredabstraction/float_option/issues"
 depends: [
   "dune" {>= "3.18"}
-  "ocaml"
+  "ocaml" {>= "5.1.0"}
   "ppx_sexp_conv"
   "ppx_optional"
   "odoc" {with-doc}