Make caches depend on C++ standard

Author: Flamefire

.github/workflows/reusable.yml

@@ -547,12 +547,14 @@ jobs:
           fetch-depth: ${{ matrix.coverage && '0' || '1' }}
 
       - name: Cache ccache
-        uses: actions/cache@2c8a9bd7457de244a408f35966fab2fb45fda9c8 # v6.0.0
+        uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
         if: env.B2_USE_CCACHE
         with:
           path: ~/.ccache
-          key: ${{matrix.os}}-${{matrix.container}}-${{matrix.xcode_app}}${{matrix.compiler}}-${{github.sha}}
-          restore-keys: ${{matrix.os}}-${{matrix.container}}-${{matrix.xcode_app}}${{matrix.compiler}}-
+          key: ${{matrix.os}}-${{matrix.container}}-${{matrix.xcode_app}}${{matrix.compiler}}-${{matrix.cxxstd}}-${{github.sha}}
+          restore-keys: |
+              ${{matrix.os}}-${{matrix.container}}-${{matrix.xcode_app}}${{matrix.compiler}}-${{matrix.cxxstd}}-
+              ${{matrix.os}}-${{matrix.container}}-${{matrix.xcode_app}}${{matrix.compiler}}-
 
       - name: Fetch Boost.CI
         uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0