capnproto-rust: 0.17.2 -> 0.20.1; add update script (#376359)

pkgs/by-name/ca/capnproto-rust/package.nix

@@ -3,19 +3,20 @@
   fetchCrate,
   rustPlatform,
   capnproto,
+  nix-update-script,
 }:
 
 rustPlatform.buildRustPackage rec {
   pname = "capnproto-rust";
-  version = "0.17.2";
+  version = "0.20.1";
 
   src = fetchCrate {
     crateName = "capnpc";
     inherit version;
-    hash = "sha256-WVjXVLVoTCAtA8a6+zaX4itAaPCWb2c0trtSsxBopO4=";
+    hash = "sha256-iLjvKxVfkAVoM4AYgr31Ud1mk3MyMPReDXv1IbKEvcE=";
   };
 
-  cargoHash = "sha256-h9YArxHnY14T8eQCS4JVItjaCjv+2dorcOVBir7r6SY=";
+  cargoHash = "sha256-KNUXIKzTlbEW7WUwqVOXjN5/6BDGEbOjbKELo0KtWDc=";
 
   postInstall = ''
     mkdir -p $out/include/capnp
@@ -26,6 +27,8 @@ rustPlatform.buildRustPackage rec {
     capnproto
   ];
 
+  passthru.updateScript = nix-update-script { };
+
   meta = with lib; {
     description = "Cap'n Proto codegen plugin for Rust";
     homepage = "https://github.com/capnproto/capnproto-rust";