Apply suggestion from ocaml/opam-repository#18524 (comment)

anmonteiro · anmonteiro · commit d0e362e7a35e · 2021-04-18T01:16:52.000-07:00
diff --git a/vercel.opam b/vercel.opam
@@ -17,7 +17,7 @@ depends: [
   "base64"
   "piaf"
   "ppx_deriving_yojson"
-  "lambda-runtime"
+  "lambda-runtime" {=version}
   "alcotest" {with-test}
 ]
 synopsis:
