build(deps): 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/linux.yml

@@ -79,7 +79,7 @@ jobs:
 
     - name: Cache Build
       id: cache-build
-      uses: actions/cache@v5
+      uses: actions/cache@v6
       with:
         path: ${{env.CCACHE_DIR}}
         key: ${{matrix.os}}-${{matrix.build_type}}-${{matrix.lib}}-${{matrix.components}}-${{matrix.gpu}}-${{matrix.metis}}-ccache-${{github.run_id}}

.github/workflows/macos.yml

@@ -48,7 +48,7 @@ jobs:
 
     - name: Cache Build
       id: cache-build
-      uses: actions/cache@v5
+      uses: actions/cache@v6
       with:
         path: ${{env.CCACHE_DIR}}
         key: ${{matrix.os}}-${{matrix.build_type}}-${{matrix.lib}}-${{matrix.components}}-${{matrix.metis}}-ccache-${{github.run_id}}

.github/workflows/windows.yml

@@ -61,7 +61,7 @@ jobs:
 
     - name: Cache Build
       id: cache-build
-      uses: actions/cache@v5
+      uses: actions/cache@v6
       with:
         path: ${{env.CCACHE_DIR}}
         key: ${{runner.os}}-${{matrix.sys}}-${{matrix.env}}-${{matrix.build_type}}-${{matrix.lib}}-${{matrix.components}}-${{matrix.metis}}-ccache-${{github.run_id}}
@@ -134,7 +134,7 @@ jobs:
     - name: Cache METIS
       if: matrix.metis == 'metis'
       id: cache-metis
-      uses: actions/cache@v5
+      uses: actions/cache@v6
       with:
         path: metis/
         key: ${{matrix.msvc}}-metis-5.1.0-${{matrix.build_type}}-shared
@@ -185,7 +185,7 @@ jobs:
 
     - name: Cache LAPACK
       id: cache-lapack
-      uses: actions/cache@v5
+      uses: actions/cache@v6
       with:
         path: |
           ${{env.CCACHE_DIR}}