Copyright date needs to be updated to include 2025

[seanPhill]

Surprisingly we missed updating the copyright for two years.

Copyright (C) 2018-2022 The Veil Core developers
should read
Copyright (C) 2018-2025 The Veil Core developers

We are still here.

We will update this with the next release, not separately, because that would be "lame". ;)

[seanPhill]

I think the cause of this was because the date had been fixed in a release, but the master branch did not have the digit incremented, so when a following release was done the date was re-inherited from the master branch.

I've got a commit (to line 8 of configure.ac) sitting in my local master branch ready for a future push, as I don't want to push a one-digit edit and Github Actions build alone.