Update setting version to 18 for libArachne release

Although it is not entirely sure yet, we are fairly certain that libArachne release will have
a setting version of 18, so it is changed by this commit. With this change, the VersionUpgrader
will be properly triggered.

Contributes to CURA-7683 and CURA-7656

resources/definitions/blv_mgn_cube_300.def.json

@@ -4,7 +4,7 @@
   "inherits": "blv_mgn_cube_base",
   "metadata": {
     "visible": true,
-    "setting_version": 16,
+    "setting_version": 18,
     "author": "wolfgangmauer",
     "manufacturer": "BLV",
     "file_formats": "text/x-gcode",

resources/definitions/blv_mgn_cube_350.def.json

@@ -4,7 +4,7 @@
   "inherits": "blv_mgn_cube_base",
   "metadata": {
     "visible": true,
-    "setting_version": 16,
+    "setting_version": 18,
     "author": "wolfgangmauer",
     "manufacturer": "BLV",
     "file_formats": "text/x-gcode",

resources/definitions/fdmextruder.def.json

@@ -6,7 +6,7 @@
         "type": "extruder",
         "author": "Ultimaker",
         "manufacturer": "Unknown",
-        "setting_version": 16,
+        "setting_version": 18,
         "visible": false,
         "position": "0"
     },

resources/definitions/fdmprinter.def.json

@@ -6,7 +6,7 @@
         "type": "machine",
         "author": "Ultimaker",
         "manufacturer": "Unknown",
-        "setting_version": 16,
+        "setting_version": 18,
         "file_formats": "text/x-gcode;model/stl;application/x-wavefront-obj;application/x3g",
         "visible": false,
         "has_materials": true,