Octez: Fix "digestif" version constraint

Author: killian-delarue

packages/octez-internal-libs/octez-internal-libs.20.1/opam

@@ -20,7 +20,7 @@ depends: [
   "fmt" { >= "0.8.7" }
   "astring"
   "bheap"
-  "digestif"
+  "digestif" { >= "0.9.0" }
   "jsonm"
   "lwt" { >= "5.7.0" }
   "mtime" { >= "2.0.0" }