work on __resource -> fxmanifest and RDR compatibility

resources/[managers]/mapmanager/fxmanifest.lua

@@ -8,7 +8,8 @@ server_scripts {
     "mapmanager_server.lua"
 }
 
-resource_manifest_version "77731fab-63ca-442c-a67b-abc70f28dfa5"
+fx_version 'adamant'
+games { 'gta5', 'rdr3' }
 
 server_export "getCurrentGameType"
 server_export "getCurrentMap"
@@ -16,4 +17,6 @@ server_export "changeGameType"
 server_export "changeMap"
 server_export "doesMapSupportGameType"
 server_export "getMaps"
-server_export "roundEnded"
+server_export "roundEnded"
+
+rdr3_warning 'I acknowledge that this is a prerelease build of RedM, and I am aware my resources *will* become incompatible once RedM ships.'

resources/[managers]/mapmanager/mapmanager_client.lua

@@ -62,6 +62,10 @@ AddEventHandler('onResourceStop', function(res)
 end)
 
 AddEventHandler('getMapDirectives', function(add)
+	if not CreateScriptVehicleGenerator then
+		return
+	end
+
     add('vehicle_generator', function(state, name)
         return function(opts)
             local x, y, z, heading