Update github action cache. (#1971)

.github/workflows/continuous.yml

@@ -61,7 +61,7 @@ jobs:
 
       - name: Cache Build
         id: cache-build
-        uses: actions/cache@v1
+        uses: actions/cache@v2
         with:
           path: ~/.ccache
           key: ${{ runner.os }}-${{ matrix.config }}-${{ matrix.static }}-cache
@@ -115,11 +115,12 @@ jobs:
 
       - name: Cache build
         id: cache-build
-        uses: actions/cache@v1
+        uses: actions/cache@v2
         with:
           path: ${{ env.appdata }}\Mozilla\sccache
           key: ${{ runner.os }}-${{ matrix.config }}-${{ matrix.static }}-cache
 
+
       - name: Prepare sccache
         run: |
           Invoke-Expression (New-Object System.Net.WebClient).DownloadString('https://get.scoop.sh')