Bump actions/cache from 4 to 6

Bumps [actions/cache](https://github.com/actions/cache) from 4 to 6.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@v4...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/kmp.yml

@@ -35,7 +35,7 @@ jobs:
         id: kotlin-version
         run: echo "version=$(.github/scripts/extract-kotlin-version.sh)" >> "$GITHUB_OUTPUT"
       - name: Cache Kotlin/Native
-        uses: actions/cache@v4
+        uses: actions/cache@v6
         with:
           path: ~/.konan
           key: kotlin-${{ steps.kotlin-version.outputs.version }}
@@ -83,7 +83,7 @@ jobs:
           sudo udevadm control --reload-rules
           sudo udevadm trigger --name-match=kvm
       - name: AVD cache
-        uses: actions/cache@v4
+        uses: actions/cache@v6
         id: avd-cache
         with:
           path: |