Bump actions/cache from 3 to 4

Bumps [actions/cache](https://github.com/actions/cache) from 3 to 4.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@v3...v4)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/master.yml

@@ -41,7 +41,7 @@ jobs:
         cabal freeze
 
     - name: Cache
-      uses: actions/cache@v4.0.0
+      uses: actions/cache@v4
       with:
         path: |
           ${{ steps.setup-haskell.outputs.cabal-store }}
@@ -83,7 +83,7 @@ jobs:
         (cd servant-quickcheck && eval $DOCTEST)
 
     - name: Save cache
-      uses: actions/cache/save@v3
+      uses: actions/cache/save@v4
       if: always()
       with:
         path: |
@@ -111,7 +111,7 @@ jobs:
         cat cabal.project
         nix-shell ghcjs.nix --run "cabal v2-update && cabal v2-freeze"
     - name: Cache
-      uses: actions/cache@v4.0.0
+      uses: actions/cache@v4
       with:
         path: |
           ~/.cabal/store
@@ -128,7 +128,7 @@ jobs:
         nix-shell ghcjs.nix --run ".github/run-ghcjs-tests.sh"
 
     - name: Save cache
-      uses: actions/cache/save@v3
+      uses: actions/cache/save@v4
       if: always()
       with:
         path: |