Update actions/checkout action to v6

.gitea/workflows/build.yaml

@@ -9,10 +9,12 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Install pnpm
-        uses: pnpm/action-setup@v5
+        uses: pnpm/action-setup@v4
+        with:
+          version: 10
 
       - name: Setup Node.js
         uses: actions/setup-node@v4