Update index.rst with a new example

[alephmelo]

The current service seems to be offline for quite a while.

[mvantellingen]

I'm not sure if we can use that domain instead. It would be best to host our own example wsdl service. Need to think about this

[alephmelo]

Ah, it makes sense - although this domain is listed in many tutorials and examples.

Let me know if I can help somehow.