update changelog for v8.0.0
update changelog for v8.0.0

Signed-off-by: Christopher Hiller <cba4593484830aa757cb097d8d9f0ea9b692b304@boneskull.com>

outsideris/mocha,adamgruber/mocha,adamgruber/mocha,outsideris/mocha,mochajs/mocha,mochajs/mocha,mochajs/mocha,adamgruber/mocha