go-grip: init at 0.5.6

pkgs/by-name/go/go-grip/package.nix

···
+{
+  buildGoModule,
+  fetchFromGitHub,
+  lib,
+  gitUpdater,
+}:
+buildGoModule rec {
+  pname = "go-grip";
+  version = "0.5.6";
+
+  src = fetchFromGitHub {
+    owner = "chrishrb";
+    repo = "go-grip";
+    tag = "v${version}";
+    hash = "sha256-c3tl5nALPqIAMSqjbbQDi6mN6M1mKJvzxxDHcj/QyuY=";
+  };
+
+  vendorHash = "sha256-aU6vo/uqJzctD7Q8HPFzHXVVJwMmlzQXhAA6LSkRAow=";
+
+  passthru.updateScript = gitUpdater { rev-prefix = "v"; };
+
+  meta = {
+    description = "Preview Markdown files locally before committing them";
+    homepage = "https://github.com/chrishrb/go-grip";
+    license = lib.licenses.mit;
+    maintainers = with lib.maintainers; [ heisfer ];
+    mainProgram = "go-grip";
+  };
+}