Add TLS v1.3 support to the bootstrapper script

[kapsiR]

Since TLS v1.2+ is the de facto standard of communication with HTTPS, we should support it that way:
develop...kapsiR:cake:ft-installer-tls-version

The domains used even don't support TLS < v1.2 anymore...

[kapsiR]

@devlead May I create a PR for that?

[pascalberger]

See https://cakebuild.net/docs/running-builds/runners/dotnet-tool#getting-the-bootstrapper / https://github.com/cake-build/resources/blob/master/dotnet-tool/build.ps1 for our current suggested bootstrapping script. We assume .NET is already installed and therefore there is no requirement to set TLS settings

[kapsiR]

This addresses the build script of cake itself: https://github.com/cake-build/cake/blob/develop/build.ps1#L14-L28

[devlead]

Sure, send a PR and we'll take a look.

[kapsiR]

Here you go: #4452