Update build.sh

build.sh

@@ -9,7 +9,7 @@ mkdir $PACKAGE_FOLDER
 cp assets/overlay.cfg $PACKAGE_FOLDER/overlay.cfg
 cp assets/overlay.png $PACKAGE_FOLDER/overlay.png
 make platform=switch -j10
-git clone -b master https://git.m4xw.net/Switch/RetroArch/RetroArch.git --depth=1
+git clone -b $BRANCH https://git.m4xw.net/Switch/RetroArch/RetroArch.git --depth=1
 cp $LIBRARY_NAME RetroArch/libretro_switch.a
 cp assets/icon.jpg RetroArch/icon.jpg
 cd RetroArch/