TcmTemplateSync: crash when using extensions parameter without value

[jhorsman]

Running TcmTemplateSync.exe with the --extensions parameter but wihtout values for that parameter will crash the application.

To reproduce run: TcmTemplateSync.exe --extensions

Error:
Unhandled Exception: System.NullReferenceException: Object reference not set to
an instance of an object.
at Tridion.Extensions.Deployment.TemplateUpload.Program.<>c__DisplayClassa.b__4(String v)
at Mono.Options.Option.Invoke(OptionContext c)
at Mono.Options.OptionSet.ParseValue(String option, OptionContext c)
at Mono.Options.OptionSet.Parse(String argument, OptionContext c)
at Mono.Options.OptionSet.Parse(IEnumerable`1 arguments)
at Tridion.Extensions.Deployment.TemplateUpload.Program.Main(String[] args)

Tested with https://github.com/willprice76/templating-dev-tools/blob/c736e772fe457f57108ef8ad413957b0d281b369/TcmTemplateSync/release/1.0/TcmTemplateSync.exe

Probably simple to fix, low prio so I am not going to fix it right away.