Nix support & automated update (#130)

* Add a nix flake

* Update flake deps and nix package's version nightly

* nix-flake: Update vendorSha256 on each push

An extra commit will be pushed only if needed

* Move flake.* into root directory

Update flake.lock

* nix-flake: Support more systems, commit hash as version

* Don't automatically update flake.lock

nix/default.nix

@@ -0,0 +1,38 @@
+let
+  # Import nixpkgs if needed
+  pkgs = import <nixpkgs> {};
+in
+  {
+    lib ? pkgs.lib,
+    buildGoModule ? pkgs.buildGoModule,
+    fetchFromGitHub ? pkgs.fetchFromGitHub,
+    installShellFiles ? pkgs.installShellFiles,
+    # version and vendorSha256 should be specified by the caller
+    version ? "latest",
+    vendorSha256,
+  }:
+    buildGoModule rec {
+      pname = "packwiz";
+      inherit version vendorSha256;
+
+      src = ./..;
+
+      nativeBuildInputs = [
+        installShellFiles
+      ];
+
+      # Install shell completions
+      postInstall = ''
+        installShellCompletion --cmd packwiz \
+          --bash <($out/bin/packwiz completion bash) \
+          --fish <($out/bin/packwiz completion fish) \
+          --zsh <($out/bin/packwiz completion zsh)
+      '';
+
+      meta = with lib; {
+        description = "A command line tool for editing and distributing Minecraft modpacks, using a git-friendly TOML format";
+        homepage = "https://packwiz.infra.link/";
+        license = licenses.mit;
+        mainProgram = "packwiz";
+      };
+    }

nix/prefetcher.nix

@@ -0,0 +1,11 @@
+{
+  sha256,
+  pkgs ? import <nixpkgs> {},
+}:
+pkgs.callPackage (import ./.) {
+  buildGoModule = pkgs.buildGo118Module;
+  vendorSha256 = sha256;
+}
+// {
+  outputHash = sha256;
+}

nix/vendor-sha256

@@ -0,0 +1 @@
+sha256-M9u7N4IrL0B4pPRQwQG5TlMaGT++w3ZKHZ0RdxEHPKk=