Change URL of firmware update page for Ultimaker 3 and S5

I just got word of a new page to read up about the firmware update. Apparently we now have to link to this one.

Contributes to issue CURA-5483.

plugins/FirmwareUpdateChecker/FirmwareUpdateCheckerJob.py

@@ -1,4 +1,4 @@
-# Copyright (c) 2017 Ultimaker B.V.
+# Copyright (c) 2018 Ultimaker B.V.
 # Cura is released under the terms of the LGPLv3 or higher.
 
 from UM.Application import Application

resources/definitions/ultimaker3.def.json

@@ -32,7 +32,7 @@
                 "http://software.ultimaker.com/jedi/releases/latest.version?utm_source=cura&utm_medium=software&utm_campaign=resources",
                 "http://software.ultimaker.com/releases/firmware/9066/stable/version.txt"
             ],
-            "update_url": "https://ultimaker.com/en/resources/20500-upgrade-firmware"
+            "update_url": "https://ultimaker.com/firmware"
         }
     },
 

resources/definitions/ultimaker3_extended.def.json

@@ -31,7 +31,7 @@
                 "http://software.ultimaker.com/jedi/releases/latest.version?utm_source=cura&utm_medium=software&utm_campaign=resources",
                 "http://software.ultimaker.com/releases/firmware/9511/stable/version.txt"
             ],
-            "update_url": "https://ultimaker.com/en/resources/20500-upgrade-firmware"
+            "update_url": "https://ultimaker.com/firmware"
         }
     },
 

resources/definitions/ultimaker_s5.def.json

@@ -34,7 +34,7 @@
         "firmware_update_info": {
             "id": 9051,
             "check_urls": ["http://software.ultimaker.com/releases/firmware/9051/stable/version.txt"],
-            "update_url": "https://ultimaker.com/en/resources/20500-upgrade-firmware"
+            "update_url": "https://ultimaker.com/firmware"
         }
     },