libwebp: upgrade 1.5.0 -> 1.6.0
(From OE-Core rev: 3ea48cca171de36f8028d01756f9c931e46bb02e)
Signed-off-by: Wang Mingyu <wangmy@fujitsu.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>