fix: CI (#50)

.github/workflows/elixir.yml

@@ -15,9 +15,9 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
 
-    - uses: cachix/install-nix-action@v19
+    - uses: cachix/install-nix-action@v22
       with:
         github_access_token: ${{ secrets.GITHUB_TOKEN }}
         extra_nix_config: |
@@ -31,13 +31,13 @@ jobs:
           substituters = https://cache.iog.io https://cache.nixos.org/
 
     - name: Restore cached nix store
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: /home/runner/nix
         key: ${{ runner.os }}-nix-${{ hashFiles('flake.lock') }}
 
     - name: Restore cached mix deps
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: deps
         key: ${{ runner.os }}-mix-${{ hashFiles('**/mix.lock') }}

flake.nix

@@ -1,31 +1,32 @@
 {
   description = "Holidefs: Definition-based national holidays in Elixir";
-
   inputs.nixpkgs.url = "github:NixOS/nixpkgs";
+  inputs.flake-utils.url = "github:numtide/flake-utils";
 
-  outputs = { self, nixpkgs }:
-    let
-      elixirOverlay = final: prev: {
-        elixir-ls = (prev.elixir-ls.override {
-          elixir = prev.beam.packages.erlangR24.elixir_1_12;
-        });
-      };
-
-      system = "x86_64-linux";
-      pkgs = import nixpkgs { inherit system; overlays = [ elixirOverlay ]; };
-    in {
-      devShells.${system} = {
-        default = pkgs.mkShell {
-          buildInputs = with pkgs; [
-            nil
-            beam.packages.erlangR24.elixir_1_12
-            elixir_ls
-          ];
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        elixirOverlay = final: prev: {
+          elixir-ls = (prev.elixir-ls.override {
+            elixir = prev.beam.packages.erlangR24.elixir_1_12;
+          });
         };
 
-        ci = pkgs.mkShell {
-          buildInputs = with pkgs; [ beam.packages.erlangR24.elixir_1_12 ];
+        pkgs = import nixpkgs { inherit system; overlays = [ elixirOverlay ]; };
+      in {
+        devShells = {
+          default = pkgs.mkShell {
+            buildInputs = with pkgs; [
+              nil
+              beam.packages.erlangR24.elixir_1_12
+              elixir_ls
+            ];
+          };
+
+          ci = pkgs.mkShell {
+            buildInputs = with pkgs; [ beam.packages.erlangR24.elixir_1_12 ];
+          };
         };
-      };
-    };
+      }
+    );
 }