specify pnpm version for actions

Author: Wyvest

.github/actions/setup-pnpm/action.yml

@@ -10,6 +10,8 @@ runs:
   steps:
     - name: Install pnpm
       uses: pnpm/action-setup@ac5bf11548bf5e19b8aadb8182072616590fa4a6
+      with:
+        version: 9
 
     - name: Install Node.js
       uses: actions/setup-node@26961cf329f22f6837d5f54c3efd76b480300ace