irmin-test: old versions require old verion of mtime

Author: samoht

packages/irmin-test/irmin-test.2.2.0/opam

@@ -17,7 +17,7 @@ depends: [
   "dune"     {>= "1.8.0"}
   "irmin" {>= "2.2.0" & < "2.3.0"}
   "alcotest" {>= "1.0.1"}
-  "mtime"    {>= "1.0.0"}
+  "mtime"    {>= "1.0.0" & < "2.0.0"}
   "metrics-unix"
 ]