fix(CI): upgrade to ubuntu 20.10

.github/workflows/main.yml

@@ -7,18 +7,17 @@ on: [push]
 
 jobs:
   build:
-
     # Machine environment:
     # https://help.github.com/en/articles/software-in-virtual-environments-for-github-actions#ubuntu-1804-lts
     # We specify the Node.js version manually below, and use versioned Chrome from Puppeteer.
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v1
-      - name: Use Node.js 16
-        uses: actions/setup-node@v1
+      - uses: actions/checkout@v4
+      - name: Use Node.js 20.9.0
+        uses: actions/setup-node@v4
         with:
-          node-version: 16
+          node-version: 20.9.0
       - name: Install dependencies
         run: yarn --frozen-lockfile --non-interactive --no-progress
       - name: Lint Demo

.nvmrc

@@ -0,0 +1 @@
+v20.9.0