revert pnpm (#30)

* revert pnpm

* back to yarn

Author: kazupon

.github/workflows/lint.yml

@@ -22,16 +22,12 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v2
-      - name: Install pnpm
-        uses: pnpm/action-setup@v2.0.1
-        with:
-          version: 6.17.0
       - name: Setup Node.js v14.x
         uses: actions/setup-node@v2
         with:
           node-version: 14
-          cache: 'pnpm'
+          cache: 'yarn'
       - name: Install
-        run: pnpm install
+        run: yarn install
       - name: Lint
-        run: pnpm run lint
+        run: yarn lint

.github/workflows/test.yml

@@ -26,16 +26,12 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v2
-      - name: Install pnpm
-        uses: pnpm/action-setup@v2.0.1
-        with:
-          version: 6.17.0
       - name: Setup Node.js ${{ matrix.node }}
         uses: actions/setup-node@v2
         with:
           node-version: ${{ matrix.node }}
-          cache: 'pnpm'
+          cache: 'yarn'
       - name: Install
-        run: pnpm install
+        run: yarn install
       - name: Test
-        run: pnpm test
+        run: yarn test