Add -y option to add-apt-repository command.

PiperOrigin-RevId: 348854578
Change-Id: I3a23da3309e9927e5c161aa6643cabfd7d7472fd

Author: hyeygit

tensorflow/tools/ci_build/install/install_pip_packages.sh

@@ -16,7 +16,7 @@
 
 set -e
 
-sudo add-apt-repository ppa:deadsnakes/ppa
+sudo add-apt-repository -y ppa:deadsnakes/ppa
 sudo apt-get update
 sudo apt-get install python3.8