Run tests in series

Running tests in parallel can lead to timeout errors - presumably because the Puppeteer Chrome instances are heavyweight and causing slowdowns?

package.json

@@ -34,7 +34,7 @@
     "serve": "node dev-server.js",
     "start": "concurrently --kill-others \"npm run dev\" \"npm run serve\"",
     "test.watch": "stencil test --spec --e2e --watchAll",
-    "test": "stencil test --spec --e2e",
+    "test": "stencil test --spec --e2e --runInBand",
     "version": "npm run build"
   },
   "devDependencies": {