ci: test vs node 20

Author: danielroe

.github/workflows/ci.yml

@@ -47,7 +47,7 @@ jobs:
       - run: npm i -g --force corepack && corepack enable
       - uses: actions/setup-node@cdca7365b2dadb8aad0a33bc7601856ffabcc48e # v4.3.0
         with:
-          node-version: 18
+          node-version: 20
           cache: "pnpm"
 
       - name: 📦 Install dependencies