Update readme

README.md

@@ -7,4 +7,5 @@
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 - Passing ```iw4-sp```, ```iw5-mod```, ```iw6-mod``` or ```s1-mod``` as the first argument will skip automatic game detection
-- Passing ```update``` will stop the launcher from launching the game
+- Passing ```update``` will stop the launcher from launching the game
+- ```no-launcher-update``` skips self-update