CI: use v1.2 also for windows, add cxx_std to key

- previous checksum problem has been fixed in: hendrikmuhs/ccache-action@657bab9

Author: fabinsch

.github/workflows/ci-linux-osx-win-conda.yml

@@ -60,17 +60,9 @@ jobs:
         mamba install julia
 
     - name: Activate ccache [Conda]
-      if: contains(matrix.os, 'macos') || contains(matrix.os, 'ubuntu')
       uses: hendrikmuhs/[email protected]
       with:
-        key: ${{ matrix.os }}-${{ matrix.type }}
-        max-size: 1G
-
-    - name: Activate ccache windows [Conda]
-      if: contains(matrix.os, 'windows')
-      uses: hendrikmuhs/[email protected]
-      with:
-        key: ${{ matrix.os }}-${{ matrix.type }}
+        key: ${{ matrix.os }}-${{ matrix.type }}-${{ matrix.cxx_std }}
         max-size: 1G
 
     - name: Print environment [Conda]