ci: use pnpm version 8 for codecov action

Author: d34dman

.github/workflows/codecov.yml

@@ -12,6 +12,8 @@ jobs:
     - uses: actions/checkout@v3
     - name: Setup pnpm
       uses: pnpm/action-setup@v3
+      with:
+        version: 8
     - name: Install requirements
       run: pnpm install
     - name: Run tests and collect coverage