nlohmann/json 3.11.3 selected-source attribution

The selected multi-header source carries these upstream SPDX copyright lines:

SPDX-FileCopyrightText: 2013-2023 Niels Lohmann <https://nlohmann.me>
SPDX-FileCopyrightText: 2016-2021 Evan Nemerson <evan@nemerson.com>
SPDX-FileCopyrightText: 2009 Florian Loitsch <https://florian.loitsch.com/>
SPDX-FileCopyrightText: 2008-2009 Björn Hoehrmann <bjoern@hoehrmann.de>
SPDX-FileCopyrightText: 2018 The Abseil Authors

The selected headers mark their combined files as MIT; the complete MIT terms
are distributed in nlohmann-json.txt. The C++11 compatibility branch in
include/nlohmann/detail/meta/cpp_future.hpp also identifies code copied from
Google Abseil commit 10cb35e459f5ecca5b2ff107635da0bfa41011b4 under
Apache-2.0. SceneIO compiles as C++17, so that fallback branch is not selected
for the binary. The complete Apache-2.0 terms are distributed in SceneIO's
root LICENSE.
