ytt: init at 0.30.0

Added carvel ytt 0.30.0 which is currently absent. Tests ran by
checkPhase currently fail due to YAML marshalling problems, but the tool
itself appears fine.

pkgs/development/tools/ytt/default.nix

@@ -0,0 +1,25 @@
+{ lib, buildGoModule, fetchFromGitHub }:
+buildGoModule rec {
+  pname = "ytt";
+  version = "0.30.0";
+
+  src = fetchFromGitHub {
+    owner = "vmware-tanzu";
+    repo = "carvel-ytt";
+    rev = "v${version}";
+    sha256 = "0v9wp15aj4r7wif8i897zwj3c6bg41b95kk7vi3a3bzin814qn6l";
+  };
+
+  goPackagePath = "github.com/vmware-tanzu/carvel-ytt";
+
+  vendorSha256 = null;
+
+  subPackages = [ "cmd/ytt" ];
+
+  meta = with lib; {
+    description = "YAML templating tool that allows configuration of complex software via reusable templates with user-provided values";
+    homepage = "https://get-ytt.io";
+    license = licenses.asl20;
+    maintainers = with maintainers; [ brodes ];
+  };
+}

pkgs/top-level/all-packages.nix

@@ -12156,6 +12156,8 @@ in
 
   yq-go = callPackage ../development/tools/yq-go { };
 
+  ytt = callPackage ../development/tools/ytt {};
+
   winpdb = callPackage ../development/tools/winpdb { };
 
   grabserial = callPackage ../development/tools/grabserial { };