Document in readme that we now support spring boot 1.5
Document in readme that we now support spring boot 1.5

[finishes #148875935] https://www.pivotaltracker.com/story/show/148875935

Signed-off-by: Can Berk Güder <ed1dfb86e8d469f3acf95218f1ef796e19057d0f@pivotal.io>

tnwang/identity-sample-apps,tnwang/identity-sample-apps,tnwang/identity-sample-apps