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/branch-markdown.yml

@@ -68,7 +68,7 @@ jobs:
         run: |
           echo "STORE_PATH=$(pnpm store path --silent)" >> $GITHUB_ENV
 
-      - uses: actions/cache@v5
+      - uses: actions/cache@v6
         if: steps.changed-files.outputs.count > 0
         name: Setup pnpm cache
         with:

.github/workflows/branch-spellcheck.yml

@@ -42,7 +42,7 @@ jobs:
         run: |
           echo "STORE_PATH=$(pnpm store path --silent)" >> $GITHUB_ENV
 
-      - uses: actions/cache@v5
+      - uses: actions/cache@v6
         name: Setup pnpm cache
         with:
           path: ${{ env.STORE_PATH }}