Update versions of GitHub actions

Author: smelc

.github/workflows/build.yml

@@ -9,8 +9,8 @@ jobs:
   tests:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2.3.4
-    - uses: cachix/install-nix-action@v13
+    - uses: actions/checkout@v5
+    - uses: cachix/install-nix-action@v31
       with:
         nix_path: nixpkgs=channel:nixos-unstable
     - run: nix-shell --run 'cabal build'

.github/workflows/lint.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v5
     - name: Install Python 3.9
       uses: actions/setup-python@v3
       with: