Update to latest pwsh for Vagrant box

What does this MR do?

Update to latest pwsh for Vagrant box

Why was this MR needed?

To have the latest PowerShell version

What's the best way to test this MR?

Start the vagrant machine and provision it (unless vagrant up provisioned it for you because it's the first time running).

vagrant up
vagrant provision

RDP inside of the machine and run:

PS C:\GitLab-Runner> $PSVersionTable

Name                           Value
----                           -----
PSVersion                      7.0.2
PSEdition                      Core
GitCommitId                    7.0.2
OS                             Microsoft Windows 10.0.17763
Platform                       Win32NT
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0