Changelog:

backend_startup_project
Add a man page backend to refman
extract_objects() supports generated sources
Python 3.6 support will be dropped in the next release
Warning if check kwarg of run_command is missing
meson rewrite can modify extra_files
meson rewrite target <target> info outputs target's extra_files
Visual Studio 2022 backend
Support for CMake <3.14 is now deprecated for CMake subprojects
Added support for sccache
install_symlink function

Signed-off-by: Rosen Penev <rosenp@gmail.com>