Bump actions/cache from 4 to 5

Bumps [actions/cache](https://github.com/actions/cache) from 4 to 5.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@v4...v5)

---
updated-dependencies:
- dependency-name: actions/cache
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/haskell-ci.yml

@@ -146,7 +146,7 @@ jobs:
         run: |
           $CABAL v2-update -v
       - name: cache (tools)
-        uses: actions/cache/restore@v4
+        uses: actions/cache/restore@v5
         with:
           key: ${{ runner.os }}-${{ matrix.compiler }}-tools-54f36d55
           path: ~/.haskell-ci-tools
@@ -165,7 +165,7 @@ jobs:
           if [ $((HCNUMVER < 91000)) -ne 0 ] ; then doctest --version ; fi
       - name: save cache (tools)
         if: always()
-        uses: actions/cache/save@v4
+        uses: actions/cache/save@v5
         with:
           key: ${{ runner.os }}-${{ matrix.compiler }}-tools-54f36d55
           path: ~/.haskell-ci-tools
@@ -210,7 +210,7 @@ jobs:
           $CABAL v2-build $ARG_COMPILER $ARG_TESTS $ARG_BENCH --dry-run all
           cabal-plan
       - name: restore cache
-        uses: actions/cache/restore@v4
+        uses: actions/cache/restore@v5
         with:
           key: ${{ runner.os }}-${{ matrix.compiler }}-${{ github.sha }}
           path: ~/.cabal/store
@@ -245,7 +245,7 @@ jobs:
           $CABAL v2-build $ARG_COMPILER --disable-tests --disable-benchmarks all
       - name: save cache
         if: always()
-        uses: actions/cache/save@v4
+        uses: actions/cache/save@v5
         with:
           key: ${{ runner.os }}-${{ matrix.compiler }}-${{ github.sha }}
           path: ~/.cabal/store