Update main.yml

Add playwright setup step, needed for running in other browsers on CI bots
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index f2f1e29..df91580 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -13,9 +13,11 @@
 
     steps:
     - uses: actions/checkout@v2
-    - uses: actions/setup-node@v1
+    - uses: actions/setup-node@v2
       with:
-        node-version: 12
+        node-version: 14
+    - name: Install operating system dependencies
+      run: npx playwright install-deps
     - name: npm install, build, and test
       run: |
         npm install