chore(deps): update actions/cache action to v2

Author: renovate-bot

.github/workflows/config.yml

@@ -44,7 +44,7 @@ jobs:
         id: yarn-cache
         run: echo "::set-output name=dir::$(yarn cache dir)"
       - name: Yarn のキャッシュファイルを取得する
-        uses: actions/cache@v1
+        uses: actions/cache@v2
         with:
           path: ${{ steps.yarn-cache.outputs.dir }}
           key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
@@ -56,7 +56,7 @@ jobs:
         # run: |
         #   gem install bundler --no-document -v 1.17.3 || true
       - name: RubyGems のキャッシュを復元する
-        uses: actions/cache@v1
+        uses: actions/cache@v2
         id: rubygems-cache
         with:
           path: vendor/bundle