Update cache action

Author: Kleidukos

.github/workflows/ci.yml

@@ -37,7 +37,7 @@ jobs:
         ghc-version: "${{ matrix.ghc }}"
         cabal-version: "latest"
     - name: Cache
-      uses: actions/cache@v3.3.2
+      uses: actions/cache@v4
       with:
         path: ${{ steps.setup-haskell.outputs.cabal-store }}
         key: ${{ runner.os }}-ghc-${{ matrix.ghc }}-cabal-${{ hashFiles('**/plan.json') }}