chore: bump actions/cache from 4 to 5

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](https://github.com/actions/cache/compare/v4...v5)

---
updated-dependencies:
- dependency-name: actions/cache
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/build.yaml

@@ -200,7 +200,7 @@ jobs:
       # force a rebuild.
       - name: Fetch prebuilt Code package from cache
         id: cache-vscode
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: lib/vscode-reh-web-*
           key: vscode-reh-package-${{ secrets.VSCODE_CACHE_VERSION }}-${{ steps.vscode-rev.outputs.rev }}-${{ hashFiles('patches/*.diff', 'ci/build/build-vscode.sh') }}
@@ -285,7 +285,7 @@ jobs:
           ./test/node_modules/.bin/playwright install-deps
           ./test/node_modules/.bin/playwright install
       - name: Cache Caddy
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         id: caddy-cache
         with:
           path: |