v1.5.0
[1.5.0] Deprecate some functions (#2582)
fix gitignore
[1.5.0] Move `zstd_errors.h` and `zdict.h` to `lib/` root
[linux-kernel] Update README with initial instructions on how to update zstd in the kernel
Add BtrFS benchmarks
[linux] Write all the patch summaries
[copyright][license] Switch to yearless copyright and some cleanup in the linux-kernel files
[contrib][linux-kernel] Add zstd_min_clevel() and zstd_max_clevel()
[kernel] Update README with SquashFS patch