chore: fix CI setup for unit tests (#8530)

Author: benmccann

.github/workflows/ci.yml

@@ -69,8 +69,7 @@ jobs:
       - uses: pnpm/[email protected]
       - uses: actions/setup-node@v3
         with:
+          node-version: ${{ matrix.node-version }}
           cache: pnpm
       - run: pnpm install
-        env:
-          SKIP_PREPARE: true
       - run: pnpm test:unit