[DPP] Bump to version 10.1.6

[Craig Edwards (Brain) (braindigitalis)]

This PR updates DPP package to 10.1.6

Our vcpkg update is built from our CI actions.

• Which triplets are supported/not supported? Have you updated the CI baseline?

  Triplets are unchanged, baseline not updated.

• Does your PR follow the maintainer guide?

  Yes

• If you have added/updated a port: Have you run ./vcpkg x-add-version --all and committed the result?

  Yes

[Billy O'Neal (BillyONeal)]

Thanks for the update! Drafting due to build failures. Additionally GPT 5.6 notes:

• DPP 10.1.6 fails to compile on arm64-linux, x64-linux, arm64-osx, arm64-windows, x64-windows, x64-windows-release, and x86-windows. The new src/dpp/cluster.cpp uses #include "discordclient.h", but the vcpkg-specific target exposes only the root include directory and the header is include/dpp/discordclient.h. Please patch it to #include <dpp/discordclient.h> (preferably upstream) and rerun CI.
• The pre-existing package builds vendored mlspp and installs vendored nlohmann-json headers, while declaring/installing only Apache-2.0 licensing. The packaged content also includes BSD-2-Clause and MIT material. Please follow up by avoiding the vendored JSON copy where possible and accurately installing/declaring all applicable license notices.

I would really like to see nlohmann-json devendored as that one can be security sensitive but that's not an absolute requirement if it was there in the previous version. If it stays vendored then it must be ACK'd in the copyright file and "license"

[Craig Edwards (Brain) (braindigitalis)]

I'm away right now, we likely won't fix this via a patch but will instead release a 10.1.7 with this specific fix set. keep this a draft for now and I'll pick this up when I return home.