bump ci cache version

Author: kateinoigakukun

.github/workflows/build-toolchain.yml

@@ -78,9 +78,9 @@ jobs:
       - uses: actions/cache@v1
         with:
           path: build-cache
-          key: ${{ matrix.target }}-sccache-v10-${{ steps.cache_timestamp.outputs.timestamp }}
+          key: ${{ matrix.target }}-sccache-v11-${{ steps.cache_timestamp.outputs.timestamp }}
           restore-keys: |
-            ${{ matrix.target }}-sccache-v10-
+            ${{ matrix.target }}-sccache-v11-
 
       - name: Select Xcode version
         if: ${{ matrix.build_os == 'macos-10.15' }}
@@ -103,6 +103,9 @@ jobs:
             ;;
           esac
 
+      - name: Check cache hit rate
+        run: sccache --show-stats
+
       - name: Upload ${{ matrix.target }} installable archive
         uses: actions/upload-artifact@v1
         with: