Bump actions/cache from 3 to 4 (#63)

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/main.yml

@@ -41,7 +41,7 @@ jobs:
           cabal configure --enable-tests --disable-documentation
           cabal build all --dry-run
       - name: Restore cached dependencies
-        uses: actions/cache/restore@v3
+        uses: actions/cache/restore@v4
         id: cache
         env:
           key: ${{ runner.os }}-ghc-${{ steps.setup.outputs.ghc-version }}-cabal-${{ steps.setup.outputs.cabal-version }}
@@ -53,7 +53,7 @@ jobs:
         if: steps.cache.outputs.cache-hit != 'true'
         run: cabal build all --only-dependencies
       - name: Save cached dependencies
-        uses: actions/cache/save@v3
+        uses: actions/cache/save@v4
         if: steps.cache.outputs.cache-hit != 'true'
         with:
           path: ${{ steps.setup.outputs.cabal-store }}