Stuck in package installation from git

On Windows, when trying to install a custom package via a git url, the package manager gets stuck with the following message:

PLEASE WAIT, INSTALLING A GIT PACKAGE

I followed the ssh instructions from here:

There are no errors in the editor and the upm logs. The last line in the upm log is about cloning my repo

Unity is stuck because ssh needs you to verify the ssh fingerprint and Unity does not check for that. You can do that by testing the ssh connection and verifying the fingerprint.