Add version info

[Irratzo]

The project's homepage https://molmod.ugent.be/deltacodesdft, section "Downloads", offers the "Delta calculation package" as zipped archive. I guess that this is equivalent to the content of this repo. However, there different versions are available (version 1.0 to version 3.1). It would be nice if a version info would be added to either this repo's README (simple) or release page (harder), so as to inform to which version on the project's homepage this repo corresponds. I guess it's version 3.1, but I am not sure. Thank you.

[wpoely86]

@Irratzo can you remove your quotation of the phishing message? Thanks.