[WASM] Update cache strategy using timestamp

Author: kateinoigakukun

.github/workflows/main.yml

@@ -28,10 +28,18 @@ jobs:
       - uses: actions/checkout@v1
         with:
           path: swift
+      - name: Prepare sccache timestamp
+        id: cache_timestamp
+        shell: cmake -P {0}
+        run: |
+          string(TIMESTAMP current_date "%Y-%m-%d-%H;%M;%S" UTC)
+          message("::set-output name=timestamp::${current_date}")
       - uses: actions/cache@v1
         with:
           path: ../build-cache
-          key: ${{ runner.os }}-sccache-v7-5.3
+          key: ${{ runner.os }}-sccache-v10-5.3-${{ steps.cache_timestamp.outputs.timestamp }}
+          restore-keys: |
+            ${{ runner.os }}-sccache-v10-5.3-
       - name: Build Linux installable archive
         run: |
           ./utils/webassembly/ci.sh
@@ -58,10 +66,18 @@ jobs:
       - uses: actions/checkout@v1
         with:
           path: swift
+      - name: Prepare sccache timestamp
+        id: cache_timestamp
+        shell: cmake -P {0}
+        run: |
+          string(TIMESTAMP current_date "%Y-%m-%d-%H;%M;%S" UTC)
+          message("::set-output name=timestamp::${current_date}")
       - uses: actions/cache@v1
         with:
           path: ../build-cache
-          key: ${{ runner.os }}-sccache-v7-5.3
+          key: ${{ runner.os }}-sccache-v10-5.3-${{ steps.cache_timestamp.outputs.timestamp }}
+          restore-keys: |
+            ${{ runner.os }}-sccache-v10-5.3-
       - name: Build macOS installable archive
         run: |
           sudo xcode-select --switch /Applications/Xcode_12_beta.app/Contents/Developer/