Merge branch 'stable-5.7'

* stable-5.7:
  Prepare 5.7.0-SNAPSHOT builds
  EGit Mylyn Github Connector v5.7.0.202001151323-m1

Change-Id: I4d93895744d42a9d0b601084d39685a96d4558b2
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>