Add pnpm install step

Author: kamiazya

.github/workflows/main.yaml

@@ -22,6 +22,8 @@ jobs:
           egress-policy: audit
       - name: Checkout Repo
         uses: actions/checkout@eef61447b9ff4aafe5dcd4e0bbf5d482be7e7871 # v4.2.1
+      - name: Setup pnpm
+        uses: pnpm/action-setup@fe02b34f77f8bc703788d5817da081398fad5dd2 # v4.0.0
       - name: Setup Node.js
         uses: actions/setup-node@0a44ba7841725637a19e28fa30b79a866c81b0a6 # v4.0.4
         with:
@@ -46,6 +48,8 @@ jobs:
           egress-policy: audit
       - name: Checkout Repo
         uses: actions/checkout@eef61447b9ff4aafe5dcd4e0bbf5d482be7e7871 # v4.2.1
+      - name: Setup pnpm
+        uses: pnpm/action-setup@fe02b34f77f8bc703788d5817da081398fad5dd2 # v4.0.0
       - name: Setup Node.js
         uses: actions/setup-node@0a44ba7841725637a19e28fa30b79a866c81b0a6 # v4.0.4
         with: