Add an option to force using local updater binary (for updater development)

logic/updater/DownloadUpdateTask.cpp

@@ -404,7 +404,7 @@ DownloadUpdateTask::processFileLists(NetJob *job,
 
 				if (isUpdater)
 				{
-#ifdef MultiMC_UPDATER_DRY_RUN
+#ifdef MultiMC_UPDATER_FORCE_LOCAL
 					QLOG_DEBUG() << "Skipping updater download and using local version.";
 #else
 					auto cache_entry = MMC->metacache()->resolveEntry("root", entry.path);