Allow SecurityProtocol to be specified for a repo

[palintir]

A parameter (securityprotocols) has been added to the psrepository type
which will accept a list of security protocols that the repository will
accept, the list can contain any values can be specified for the
ServicePointManager.SecurityProtocol Property (see
https://docs.microsoft.com/en-us/dotnet/api/system.net.servicepointmanager.securityprotocol)

e.g.

psrepository { 'psrepo':
    ensure              => present,
    source_location     => 'https://local.repo.domain/',
    installation_policy => 'trusted',
    securityprotocols   => [ TLS11, TLS12 ]
}

This is to resolve an SSL connection issue that can occur if the
PowerShell repository enforces the use of a specific TLS version, but
the Windows client has a default protocol version that is lower.

[hbuckle]

Hi @palintir, sorry for the delayed response. Thinking about this would it make sense to just set TLS 1,2 and 3 support by default for all commands - that way we aren't reliant on the psrepository being in the catalog for the package commands to work. What do you think?

[palintir]

@hbuckle I was initially going to do this but I was concerned that it might cause issues for others, so I decided to make it user controllable, but I have no objections to doing it this way if that's what you suggest.

[hbuckle]

The only issue I can think of would be if you wanted to prevent connections to TLS1.0 or TLS 1.1 repos.
I see for .NET 4.7 or Core SystemDefault can be set - what about setting SystemDefault if it is available, otherwise setting 1, 1.1 and 1.2 - that way if you need to control things you can use the system settings?