fix: handle KeyboardInterrupt exception

Using Ctrl+C to interrupt the program won't display a big ugly error
anymore.

kosmorro

@@ -23,4 +23,7 @@ from kosmorrolib.main import main
 locale.setlocale(locale.LC_ALL, '')
 
 if __name__ == '__main__':
-    sys.exit(main())
+    try:
+        sys.exit(main())
+    except KeyboardInterrupt:
+        sys.exit(1)