ci: Update GitHub Actions checkout action to v5 and add fmt component

Author: triarius

.github/workflows/ci.yaml

@@ -5,32 +5,34 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v5
     - uses: dtolnay/rust-toolchain@stable
     - run: cargo build --verbose
   nix:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v5
     - uses: cachix/install-nix-action@v27
     - run: nix build
     - run: nix flake check
   fmt:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v5
     - uses: dtolnay/rust-toolchain@stable
+      with:
+        components: rustfmt
     - run: cargo fmt --verbose --all --check
   test:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v5
     - uses: dtolnay/rust-toolchain@stable
     - run: cargo test -- --nocapture
   clippy:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v5
     - uses: dtolnay/rust-toolchain@stable
       with:
         components: clippy