fix(ci): update workflows to use pnpm

.github/workflows/main.yml

@@ -17,21 +17,21 @@ jobs:
         uses: actions/cache@v1
         with:
           path: node_modules
-          key: nodeModules-${{ hashFiles('**/yarn.lock') }}
+          key: nodeModules-${{ hashFiles('**/pnpm-lock.yaml') }}
           restore-keys: |
             nodeModules-
 
       - name: Install dependencies
-        run: yarn install --frozen-lockfile
+        run: pnpm install --frozen-lockfile
         env:
           CI: true
 
       - name: Test
-        run: yarn test
+        run: pnpm test
         env:
           CI: true
 
       - name: Build
-        run: yarn build
+        run: pnpm build
         env:
           CI: true