Download the debian package from the official citrix homepage. Choose the “Web Package (Web Receiver onlyi)” download.
sudo apt install libwebkitgtk-1.0-0
sudo dpkg -i icaclientWeb_13.4.0.10109380_amd64.deb
sudo ln -s /usr/share/ca-certificates/mozilla/* /opt/Citrix/ICAClient/keystore/cacerts/
Your downloaded version of icaclientWeb may differ from this one.