feat(uptime): add redirect error (#387)

Author: JoshFerge

schemas/uptime-results.v1.schema.json

@@ -18,7 +18,8 @@
         "dns_error",
         "failure",
         "tls_error",
-        "connection_error"
+        "connection_error",
+        "redirect_error"
       ]
     },
     "RequestType": {