chore: add flake

Author: tricktron

.gitignore

@@ -6,4 +6,6 @@ dist/
 test/testFixture/.vscode
 *.vsix
 .DS_Store
-test-resources
+test-resources
+.envrc
+.direnv

flake.lock

@@ -0,0 +1,29 @@
+{
+    description             = "vscode-yaml-dev-shell";
+    inputs.nixpkgs.url      = "github:NixOS/nixpkgs";
+    inputs.flake-utils.url  = "github:numtide/flake-utils";
+
+    outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachSystem
+    [
+        "x86_64-darwin"
+        "aarch64-darwin"
+        "x86_64-linux"
+        "aarch64-linux"
+    ]
+    (system:
+
+    let
+        pkgs = nixpkgs.legacyPackages.${system};
+    in
+    {
+        devShells.default = pkgs.mkShell
+        {
+            packages = with pkgs;
+            [
+                nodejs-16_x
+                yarn
+            ];
+        };
+    });
+}