mirage-crypto-ec: require recent asn1-combinators

Author: hannesm

Diff for: mirage-crypto-ec.opam

@@ -27,7 +27,7 @@ bug-reports: "https://github.com/mirage/mirage-crypto/issues"
 depends: [
   "dune" {>= "2.6"}
   "alcotest" {with-test}
-  "asn1-combinators" {with-test}
+  "asn1-combinators" {with-test & >= "0.2.5"}
   "ocaml" {>= "4.08.0"}
   "cstruct" {>= "3.5.0"}
   "dune-configurator"