Update Doc

[yasirroni]

The Doc in https://blink1073.github.io/oct2py/ is pointed to 4.0.6, that is too old. If you need my help to make PR, I might be able to help. Thanks.

[blink1073]

I had forgotten to update the link to point to https://oct2py.readthedocs.io/en/latest/, thanks for the heads up!