Failed to build selenium in Ubuntu 18.04

[wwang2016]

Hi,

I am on Ubuntu 18.04 (Windows subsystems for Linux).

I ran into error after
docker build -t selenium .

The following is the error:
###########################################################
Cannot add PPA: 'ppa:~jonathonf/ubuntu/pepperflashplugin-nonfree'.
The user named '~jonathonf' has no PPA named 'ubuntu/pepperflashplugin-nonfree'
Please choose from the following available PPAs:

• 'ansible': Ansible
• 'atslang': ATS2 programming language
• 'backports': Backport collection
• 'barrier': Barrier
• 'bazel': Bazel
• 'byobu': Byobu
• 'calibre': Calibre
• 'clementine': Clementine
• 'compton': Compton
• 'cpan': Packaged CPAN modules
• 'cuda': CUDA tools
• 'debhelper': debhelper
• 'debhelper-10': debhelper 10
• 'debhelper-11': debhelper 11
• 'debhelper-12': debhelper 12
• 'debhelper-trusty': debhelper for trusty

###########################################################

Please make sure that the boxes below are checked before you submit your issue. Thank you!

Operating System

• I provided my operating system name and version, e.g. output of uname -a
  Linux 4.4.0-18362-Microsoft #476-Microsoft Fri Nov 01 16:53:00 PST 2019 x86_64 x86_64 x86_64 GNU/Linux

Image version

• If I don't have latest version of this image and can't upgrade, I will specify which one I'm using.
  Could not build the image

Docker version

• If I don't have latest version of docker I will specify which version with docker --version output
  Docker version 19.03.5, build 633a0ea838

Docker-Compose

• If I don't have latest version of docker-compose I will specify which version with docker-compose --version output
  docker-compose version 1.25.1, build a82fef0