File LICENSES/SPDX-header-for-documentation.txt artifact 0374f3b1da part of check-in 01225604ab

<!-- Copyright 2021 The Libfossil Authors, see LICENSES/CC-BY-SA-4.0.txt -->

<!-- SPDX-License-Identifier: CC-BY-SA-4.0 -->
<!-- SPDX-FileCopyrightText: 2021 The Libfossil Authors -->
<!-- SPDX-ArtifactOfProjectName: Libfossil -->
<!-- SPDX-FileType: Documentation -->
<!-- SPDX-FileComment: Original by Stephan Beal, 2021 -->