After repaving my machine and installing the latest version of posh-git I noticed that my Powershell profile was no longer working properly.
I was using the Start-SshAgent cmdlet to load my SSH keys and well, it was no longer recognized.
When I checked the GitHub repository, it was not immediately clear that these have been moved to a separate project: posh-sshell. Follow the instructions (or clone the repository), and include this new Powershell module as well in your profile!