chore(deps): bump actions/cache from 4 to 6 (#1281)

* chore(deps): 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](https://github.com/actions/cache/compare/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>

* chore(ci): allow actions/cache v6 in the Snap workflow policy

The Snap supply-chain policy test pins the exact major of every action
the build workflow may use, so bumping actions/cache in the workflow
without updating BUILD_ACTION_ALLOWLIST fails
publish-snap-workflow.test.mjs.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: 4gray <serega05@gmail.com>
Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

.github/workflows/build-and-make.yaml

@@ -86,7 +86,7 @@ jobs:
 
             - name: Restore pinned Linux runtime and immutable source inputs
               id: linux-runtime-cache
-              uses: actions/cache@v4
+              uses: actions/cache@v6
               with:
                   path: |
                       vendor/embedded-mpv/linux-x64/include
@@ -525,7 +525,7 @@ jobs:
               # after the macOS Embedded MPV artifacts are built and manually tested.
               if: matrix.embedded_mpv_platform && matrix.os != 'linux' && !startsWith(github.ref, 'refs/tags/v') && (github.event_name == 'pull_request' || github.ref == 'refs/heads/master')
               id: embedded-mpv-runtime-cache
-              uses: actions/cache/restore@v4
+              uses: actions/cache/restore@v6
               with:
                   path: |
                       vendor/embedded-mpv/${{ matrix.embedded_mpv_platform }}-${{ matrix.embedded_mpv_arch }}/include
@@ -1119,7 +1119,7 @@ jobs:
               # TEMPORARY ARTIFACT TEST: remove `|| github.ref == 'refs/heads/master'`
               # after the macOS Embedded MPV artifacts are built and manually tested.
               if: matrix.embedded_mpv_platform && matrix.os != 'linux' && !startsWith(github.ref, 'refs/tags/v') && github.repository == '4gray/iptvnator' && github.event_name != 'pull_request' && github.ref == 'refs/heads/master' && steps.embedded-mpv-runtime-cache.outputs.cache-hit != 'true'
-              uses: actions/cache/save@v4
+              uses: actions/cache/save@v6
               with:
                   path: |
                       vendor/embedded-mpv/${{ matrix.embedded_mpv_platform }}-${{ matrix.embedded_mpv_arch }}/include