Add Marvel Rivals (EGS) fixes (#311)

* Add Marvel Rivals (EGS) fixes

Replace target exe and set `SteamDeck=1`

* Update umu-2767030.py

Author: termdisc

gamefixes-egs/umu-2767030.py

@@ -0,0 +1,13 @@
+"""Game fix for Marvel Rivals"""
+# EGS-ID 575efd0b5dd54429b035ffc8fe2d36d0
+
+from protonfixes import util
+
+
+def main() -> None:
+
+    util.replace_command('epic_launch_helper.exe', 'MarvelRivals_Launcher.exe')
+    
+    # Set SteamDeck=1 to be able to launch the game
+    util.set_environment('SteamDeck', '1')
+