Update package.json

Update with latest release of api

Author: mbrevda

package.json

@@ -20,6 +20,6 @@
     "@actions/core": "^1.2.6",
     "@actions/github": "^4.0.0",
     "ejs": "^3.1.6",
-    "webpagetest": "^0.4.0"
+    "webpagetest": "^0.5.1"
   }
 }