add pnpm action

Author: oddcelot

.github/workflows/main.yml

@@ -12,7 +12,14 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - uses: pnpm/action-setup@v4
+        name: Install pnpm
+        with:
+          version: 10
+          run_install: false
 
       - name: install
         run: pnpm i