apt-get update shows "bionic-getdeb Release' does not have a Release file" on 18.04

I was trying to install pycharm on ubuntu bionic beaver(18.04).

I tried the following commands:

 sudo sh -c 'echo "deb http://archive.getdeb.net/ubuntu $(lsb_release -sc)-getdeb apps" >>  /etc/apt/sources.list.d/getdeb.list'
 wget -q -O - http://archive.getdeb.net/getdeb-archive.key | sudo apt-key add -
 sudo apt update

But apt update shows the following:

Hit:1 http://archive.canonical.com/ubuntu bionic InRelease            
Hit:2 http://in.archive.ubuntu.com/ubuntu bionic InRelease            
Ign:3 http://screenshots.getdeb.net bionic-getdeb InRelease           
Err:4 http://screenshots.getdeb.net bionic-getdeb Release   404  Not
Found [IP: 104.28.24.125 80] Reading package lists... Done N: Ignoring
file 'getdeb.list.bck' in directory '/etc/apt/sources.list.d/' as it

has an invalid filename extension E: The repository
'http://archive.getdeb.net/ubuntu bionic-getdeb Release' does not have
a Release file. N: Updating from such a repository can't be done
securely, and is therefore disabled by default. N: See apt-secure(8)
manpage for repository creation and user configuration details.

I tried many on-line solutions like changing server from main to India and vice versa.But not able to correct the problem. Also the link http://archive.getdeb.net/ubuntu gives 404 error.