Bump launcher version number to 1.2.0

Author: Christopher Liu

setup.py

@@ -2,7 +2,7 @@
 import os
 
 setup(name='Music Blocks Launcher',
-    version='1.1.4',
+    version='1.2.0',
     description='Flatpak launcher for Music Blocks',
     url="https://github.com/sugarlabs/musicblocks-launcher",
     data_files=[