fix: corriger les noms de fichiers dans CMakeLists.txt

- Renommage de `LaunchGameSolo.cpp` en `launchGameSolo.cpp`.
- Renommage de `LaunchGameSolo.h` en `launchGameSolo.h`.
- Renommage de `LaunchGameMulti.cpp` en `launchGameMulti.cpp`.
- Renommage de `LaunchGameMulti.h` en `launchGameMulti.h`.

CMakeLists.txt

@@ -42,10 +42,10 @@ add_executable(bloubloulespoissons main.cpp
         Utility/close.cpp
         Utility/close.h
         Utility/music.h
-        Game/LaunchGameSolo.cpp
-        Game/LaunchGameSolo.h
-        Game/LaunchGameMulti.cpp
-        Game/LaunchGameMulti.h
+        Game/launchGameSolo.cpp
+        Game/launchGameSolo.h
+        Game/launchGameMulti.cpp
+        Game/launchGameMulti.h
 )
 
 # Lier SDL2 et SDL2_image