package zsh-common 5.8-3ubuntu1 failed to install/upgrade: conffile difference visualizer subprocess returned error exit status 127

I had custom zsh configuration scripts in /etc/zsh/ that apparently did not sit well as I tried to update from Ubuntu 18.04 to 20.04. The scripts are attached.

ProblemType: Package
DistroRelease: Ubuntu 20.04
Package: zsh-common 5.8-3ubuntu1
ProcVersionSignature: Ubuntu 5.3.0-1019.21~18.04.1-aws 5.3.18
Uname: Linux 5.3.0-1019-aws x86_64
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
CasperMD5CheckResult: skip
Date: Wed May 27 17:29:03 2020
Ec2AMI: ami-0bbe6b35405ecebdb
Ec2AMIManifest: (unknown)
Ec2AvailabilityZone: us-west-2a
Ec2InstanceType: t2.micro
Ec2Kernel: unavailable
Ec2Ramdisk: unavailable
ErrorMessage: conffile difference visualizer subprocess returned error exit status 127
PackageArchitecture: all
Python3Details: /usr/bin/python3.8, Python 3.8.2, python3-minimal, 3.8.2-0ubuntu2
PythonDetails: /usr/bin/python2.7, Python 2.7.18rc1, python-is-python2, 2.7.17-4
RelatedPackageVersions:
 dpkg 1.19.7ubuntu3
 apt 2.0.2ubuntu0.1
SourcePackage: zsh
Title: package zsh-common 5.8-3ubuntu1 failed to install/upgrade: conffile difference visualizer subprocess returned error exit status 127
UpgradeStatus: Upgraded to focal on 2020-05-27 (0 days ago)
mtime.conffile..etc.zsh.newuser.zshrc.recommended: 2020-05-27T15:07:12.847387
mtime.conffile..etc.zsh.zshenv: 2020-05-27T15:07:12.847387
mtime.conffile..etc.zsh.zshrc: 2020-05-27T15:07:12.847387