fix: ensure pnpm is installed before dependency installation

Author: devashish2024

.github/workflows/types.yml

@@ -24,6 +24,9 @@ jobs:
         with:
           node-version: '20'
 
+      - name: Install pnpm
+        run: npm install -g pnpm
+
       - name: Install dependencies
         run: pnpm install --legacy-peer-deps