updated changelog 1.4.x github changelog links
updated changelog 1.4.x github changelog links

Signed-off-by: Sean Porter <482c2ce9353f7f14d23d7195073051bbd68d0368@gmail.com>

sensu/sensu-docs,sensu/sensu-docs,sensu/sensu-docs,sensu/sensu-docs,sensu/sensu-docs