Install Powershell in Ubuntu 17.04

Download libicu55 package from http://packages.ubuntu.com/en/xenial/amd64/libicu55/download

wget http://security.ubuntu.com/ubuntu/pool/main/i/icu/libicu55_55.1-7ubuntu0.4_amd64.deb
sudo apt install ./libicu55_55.1-7ubuntu0.4_amd64.deb

If the sudo apt install fails, download the file directly from the provided link via the browser. Then open it with Software Install.

Then follow instructions for 16.04

...
sudo apt install -y powershell

Source: https://asknicks.blogspot.ru/2017/05/install-powershell-on-ubuntu-17.html

Download the AppImage version and follow the instructions:

Using a recent Linux distribution, download the AppImage PowerShell-6.0.0-alpha.18-x86_64.AppImage from the releases page onto the Linux machine.

Then execute the following in the terminal:

chmod a+x PowerShell-6.0.0-beta.5-x86_64.AppImage
./PowerShell-6.0.0-beta.5-x86_64.AppImage

The AppImage lets you run PowerShell without installing it. It is a portable application that bundles PowerShell and its dependencies (including .NET Core's system dependencies) into one cohesive package. This package works independently of the user's Linux distribution, and is a single binary.

Microsoft do not have packages for 17.04 yet. Take a look at their github:

The problem you have is their package relies on libicu55, but 17.04 does not have that package in its repositories. Unless you build from source, you will not be able to install their public Powershell packages.