update release notes for v0.39.0
update release notes for v0.39.0

jbayer/concourse,zachgersh/concourse,Amit-PivotalLabs/concourse,holgero/concourse,longnguyen11288/concourse,zachgersh/concourse,concourse/concourse,zachgersh/concourse,CloudCredo/concourse,sedouard/concourse,cjcjameson/concourse,CloudCredo/concourse,concourse/concourse,sedouard/concourse,sedouard/concourse,squeedee/concourse,Amit-PivotalLabs/concourse,concourse/concourse,holgero/concourse,Amit-PivotalLabs/concourse,beni55/concourse,cjcjameson/concourse,squeedee/concourse,jbayer/concourse,longnguyen11288/concourse,squeedee/concourse,concourse/concourse,longnguyen11288/concourse,concourse/concourse,cjcjameson/concourse,jbayer/concourse,beni55/concourse,beni55/concourse,CloudCredo/concourse,holgero/concourse