Added opam file

nombres.opam

@@ -0,0 +1,27 @@
+# This file is generated by dune, edit dune-project instead
+opam-version: "2.0"
+description: """
+Convert ints into french.
+
+Some references:
+- https://leconjugueur.lefigaro.fr/frlesnombres.php
+- https://www.miakinen.net/vrac/nombres
+- https://www.dcode.fr/ecriture-nombre-lettres
+"""
+depends: [
+  "dune" {>= "2.0"}
+]
+build: [
+  ["dune" "subst"] {pinned}
+  [
+    "dune"
+    "build"
+    "-p"
+    name
+    "-j"
+    jobs
+    "@install"
+    "@runtest" {with-test}
+    "@doc" {with-doc}
+  ]
+]