package/python-bleak: depend on python3

python-bleak doesn't support python2.

Fixes:
 - http://autobuild.buildroot.net/results/22e6139a221e64ce96e23d68a58b60074fc95473/

Signed-off-by: Asaf Kahlon <asafka7@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/python-bleak/Config.in

@@ -1,5 +1,6 @@
 config BR2_PACKAGE_PYTHON_BLEAK
 	bool "python-bleak"
+	depends on BR2_PACKAGE_PYTHON3
 	select BR2_PACKAGE_PYTHON_TXDBUS # runtime
 	help
 	  Bluetooth Low Energy platform Agnostic Klient.