mvfst: add update script

(cherry picked from commit 0931562600)
(cherry picked from commit 8c231c9ef7408bee409372f09f138288c1069737)

pkgs/by-name/mv/mvfst/package.nix

@@ -17,6 +17,8 @@
   fizz,
 
   gtest,
+
+  nix-update-script,
 }:
 
 stdenv.mkDerivation (finalAttrs: {
@@ -132,6 +134,8 @@ stdenv.mkDerivation (finalAttrs: {
     remove-references-to -t ${gtest.dev} $out/lib/*
   '';
 
+  passthru.updateScript = nix-update-script { };
+
   meta = {
     description = "Implementation of the QUIC transport protocol";
     homepage = "https://github.com/facebook/mvfst";