gitlab-ci-ls: init at 0.21.1

Language Server that works together with yamlls[1] to provide
autocompletion for GitLab CI configurations.

[1] https://github.com/redhat-developer/yaml-language-server

pkgs/by-name/gi/gitlab-ci-ls/package.nix

@@ -0,0 +1,38 @@
+{
+  rustPlatform,
+  lib,
+  fetchFromGitHub,
+  darwin,
+  openssl,
+  pkg-config,
+  stdenv,
+}:
+
+rustPlatform.buildRustPackage rec {
+  pname = "gitlab-ci-ls";
+  version = "0.21.1";
+  src = fetchFromGitHub {
+    owner = "alesbrelih";
+    repo = "gitlab-ci-ls";
+    rev = "${version}";
+    hash = "sha256-0aVwI+E/UmYDSQDArQZsaNc0jDXXOG/zDr/5o0I1aLw=";
+  };
+
+  cargoHash = "sha256-rZXIc9O+pIdR/M8kV7judiHTCwnKcX+7P1LWEqZLeD8=";
+
+  nativeBuildInputs = [ pkg-config ];
+  buildInputs =
+    [ openssl ]
+    ++ lib.optionals stdenv.isDarwin [
+      darwin.apple_sdk.frameworks.SystemConfiguration
+    ];
+
+  meta = with lib; {
+    homepage = "https://github.com/alesbrelih/gitlab-ci-ls";
+    description = "GitLab CI Language Server (gitlab-ci-ls)";
+    license = licenses.mit;
+    maintainers = with maintainers; [ ma27 ];
+    platforms = platforms.unix;
+    mainProgram = "gitlab-ci-ls";
+  };
+}