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](actions/cache@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>

Author: dependabot[bot]

.github/workflows/build.yml

@@ -64,7 +64,7 @@ jobs:
       uses: actions/checkout@v4
     - name: Cache bzip2
       id: cache
-      uses: actions/cache@v4
+      uses: actions/cache@v5
       with:
         path: ${{ github.workspace }}/install/bz2
         key: bz2-${{ needs.fetch.outputs.bz2 }}-${{ matrix.build.host }}
@@ -112,7 +112,7 @@ jobs:
       uses: actions/checkout@v4
     - name: Cache libffi
       id: cache
-      uses: actions/cache@v4
+      uses: actions/cache@v5
       with:
         path: ${{ github.workspace }}/install/ffi
         key: ffi-${{ needs.fetch.outputs.ffi }}-${{ matrix.build.host }}
@@ -179,7 +179,7 @@ jobs:
       uses: actions/checkout@v4
     - name: Cache XZ Utils
       id: cache
-      uses: actions/cache@v4
+      uses: actions/cache@v5
       with:
         path: ${{ github.workspace }}/install/xz
         key: xz-${{ needs.fetch.outputs.xz }}-${{ matrix.build.host }}