Vendor dependencies for 0.3.0 release

vendor/sharded-slab/flake.nix

@@ -0,0 +1,28 @@
+# in flake.nix
+{
+  description =
+    "Flake containing a development shell for the `sharded-slab` crate";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs = {
+        nixpkgs.follows = "nixpkgs";
+        flake-utils.follows = "flake-utils";
+      };
+    };
+  };
+
+  outputs = { self, nixpkgs, flake-utils, rust-overlay }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        overlays = [ (import rust-overlay) ];
+        pkgs = import nixpkgs { inherit system overlays; };
+        rustToolchain = pkgs.pkgsBuildHost.rust-bin.stable.latest.default;
+        nativeBuildInputs = with pkgs; [ rustToolchain pkg-config ];
+      in with pkgs; {
+        devShells.default = mkShell { inherit nativeBuildInputs; };
+      });
+}