Use pnpm/action-setup

- Fixes missing pnpm executable CI error

Author: Pytal

.github/workflows/ci.yml

@@ -12,13 +12,15 @@ jobs:
 
     steps:
       - uses: actions/checkout@v2
+      - name: Setup pnpm
+        uses: pnpm/[email protected]
+        with:
+          version: 6
       - uses: actions/setup-node@v2
         with:
           node-version: 16
           cache: pnpm
           registry-url: https://registry.npmjs.org
-      - name: Setup pnpm
-        run: npm add -g pnpm@6
       - name: Install dependencies
         run: pnpm install
       - name: Check formatting

.github/workflows/release.yml

@@ -13,13 +13,15 @@ jobs:
 
     steps:
       - uses: actions/checkout@v2
+      - name: Setup pnpm
+        uses: pnpm/[email protected]
+        with:
+          version: 6
       - uses: actions/setup-node@v2
         with:
           node-version: 16
           cache: pnpm
           registry-url: https://registry.npmjs.org
-      - name: Setup pnpm
-        run: npm add -g pnpm@6
       - name: Install dependencies
         run: pnpm install
       - name: Check formatting