Update license document.
treedf9a2436377e90539246c5e8d1ea0e301a71b6fa
-rw-r--r-- 7540 .clang-format
-rw-r--r-- 1740 .clang-tidy
-rw-r--r-- 1145 .editorconfig
-rw-r--r-- 3377 .git-blame-ignore-revs
drwxr-xr-x - .gitea
drwxr-xr-x - .github
-rw-r--r-- 1271 .gitignore
-rw-r--r-- 79444 CMakeLists.txt
-rw-r--r-- 302 COPYING
-rw-r--r-- 20155 GNUmakefile
-rw-r--r-- 1206 README.md
drwxr-xr-x - build_files
drwxr-xr-x - doc
drwxr-xr-x - extern
drwxr-xr-x - intern
drwxr-xr-x - locale
-rw-r--r-- 3615 make.bat
-rw-r--r-- 2087 pyproject.toml
drwxr-xr-x - release
drwxr-xr-x - scripts
drwxr-xr-x - source
drwxr-xr-x - tests
drwxr-xr-x - tools