Upgrade CI nodejs to 20 (#124)

Author: amyreese

.github/workflows/build.yml

@@ -49,7 +49,7 @@ jobs:
           python-version: "3.10"
       - uses: actions/setup-node@v3
         with:
-          node-version: 18
+          node-version: 20
       - shell: bash
         run: python -m pip install -U pip nox
       - name: System runtime info