Update @web/test-runner to work with M1 macs

@web/test-runner was using an older version of puppeteer, which wasn't working for M1 Macs. Now it's updated to a newer version.

Author: jbuckner

package.json

@@ -30,7 +30,7 @@
     "@typescript-eslint/eslint-plugin": "^4.16.1",
     "@typescript-eslint/parser": "^4.16.1",
     "@web/dev-server": "^0.1.1",
-    "@web/test-runner": "^0.11.5",
+    "@web/test-runner": "^0.13.15",
     "concurrently": "^5.3.0",
     "eslint": "^7.21.0",
     "eslint-config-prettier": "^6.11.0",
@@ -57,7 +57,9 @@
         "error"
       ],
       "no-shadow": "off",
-      "@typescript-eslint/no-shadow": ["error"],
+      "@typescript-eslint/no-shadow": [
+        "error"
+      ],
       "class-methods-use-this": "off",
       "import/no-unresolved": "off",
       "import/extensions": [