buildkite-agent-metrics: 5.2.1 -> 5.7.0

pkgs/servers/monitoring/buildkite-agent-metrics/default.nix

···
 { lib
 , buildGoModule
 , fetchFromGitHub
-, fetchpatch
 }:
 buildGoModule rec {
   pname = "buildkite-agent-metrics";
-  version = "5.2.1";
+  version = "5.7.0";
 
   outputs = [ "out" "lambda" ];
 
···
     owner = "buildkite";
     repo = "buildkite-agent-metrics";
     rev = "v${version}";
-    sha256 = "XZYVCSJ/DIwoLrz37aQ3yW3RUhOhorY8L1AsAWxywcg=";
+    hash = "sha256-+DK8OP/rOWIBw+5Fprd5gzFo1rJDkDt4G20iUVmrfLw=";
   };
 
-  vendorSha256 = "UIkU3i45IEXWHdiakTj7f4W9kR49k4A93msfkqeXmQQ=";
-
-  patches = [
-    # Necessary to support passing the agent token in an env var, rather than on
-    # the command line. Should be removed upon the next release.
-    (fetchpatch {
-      name = "BUILDKITE_AGENT_TOKEN-env-var.patch";
-      url = "https://github.com/buildkite/buildkite-agent-metrics/commit/6c40b478b95f0e05fc12b87158222a9ff68169e0.patch";
-      sha256 = "Y4m9qGyPIROSqOY6G6xRQfFENEG4bFF3q5dZcHI4XiY=";
-    })
-  ];
+  vendorHash = "sha256-QfvHTJQEG5nvJy5ZZ9c66JYWMcR9Irow8OOyqDDjQN0=";
 
   postInstall = ''
     mkdir -p $lambda/bin