Bump actions/cache from 5 to 6

Bumps [actions/cache](https://github.com/actions/cache) from 5 to 6.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@v5...v6)

---
updated-dependencies:
- dependency-name: actions/cache
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/pre-commit.yml

@@ -11,7 +11,7 @@ jobs:
     steps:
     - uses: actions/checkout@v6
     - uses: actions/setup-python@v6
-    - uses: actions/cache@v5
+    - uses: actions/cache@v6
       with:
         path: ~/.cache/pre-commit
         key: pre-commit|${{ env.PY }}|${{ hashFiles('.pre-commit-config.yaml') }}

.github/workflows/test.yaml

@@ -21,7 +21,7 @@ jobs:
     steps:
       - uses: actions/checkout@v6
       - name: Cache conda
-        uses: actions/cache@v5
+        uses: actions/cache@v6
         env:
           # Increase this value to reset cache if ci/environment.yml has not changed
           CACHE_NUMBER: 0