Pin ppxlib version

Firobe · Firobe · commit 508baea8356e · 2022-05-30T12:58:05.000+02:00
diff --git a/h_list.opam b/h_list.opam
@@ -14,7 +14,7 @@ url {
 }
 depends: [
   "dune"                {build & >= "2.0"}
-  "ppxlib"
+  "ppxlib"              {>= "v0.25.0"}
 ]
 descr: "
 Heterogeneous lists
diff --git a/ppx_snarky.opam b/ppx_snarky.opam
@@ -15,7 +15,7 @@ url {
 depends: [
   "ocaml" {>= "4.07.0"}
   "core" {>= "v0.12" & < "v0.14" }
-  "ppxlib"
+  "ppxlib" {>= "v0.25.0}
   "ppx_tools"
   "ppx_sexp_conv"
   "dune"                {build & >= "2.0"}
