Fixed (#841)

This is a fix for #841 and supporting test.
OK, so we're relying on the coincidence that AutoFixture suffixes the string with a GUID. I can see why it works, but I think I'd rather have things a bit more transparent, e.g.

```C#
[Theory]
[InlineData("", "", "")]
[InlineData("1.0.1", "1.0.1", "")]
[InlineData("1.0.1-alpha", "1.0.1", "alpha")]
[InlineData("1.0.1-beta-2", "1.0.1", "beta-2")]
public void ParsesVersionAndSpecialVersion(string versionString, string expectedVersion, string expectedSpecialVersion)
{
    ...
}
```

This single theory could replace all the test currently in the file.