build(deps): bump actions/cache from 3 to 4 (#67)

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

.github/workflows/ci.yml

@@ -85,7 +85,7 @@ jobs:
 
       - name: Restore PLT cache
         id: plt_cache_restore
-        uses: actions/cache/restore@v3
+        uses: actions/cache/restore@v4
         with:
           key: |
             plts-${{ runner.os }}-${{ steps.beam.outputs.otp-version }}-${{ steps.beam.outputs.elixir-version }}-${{ hashFiles('**/mix.lock') }}
@@ -101,7 +101,7 @@ jobs:
       - name: Save PLT cache
         id: plt_cache_save
         if: steps.plt_cache_restore.outputs.cache-hit != 'true'
-        uses: actions/cache/save@v3
+        uses: actions/cache/save@v4
         with:
           key: |
             plts-${{ runner.os }}-${{ steps.beam.outputs.otp-version }}-${{ steps.beam.outputs.elixir-version }}-${{ hashFiles('**/mix.lock') }}