Bump actions/cache from 4 to 5 (#53)

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
...

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

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -54,7 +54,7 @@ jobs:
           KMP_DUPLICATE_LIB_OK: "TRUE"
 
       - name: Cache conda
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         env:
           # Increase this value to reset cache if .github/environment.yml has not changed
           CACHE_NUMBER: 2