492212: [release] release Mylyn 3.20 (update version)

Task-Url: https://bugs.eclipse.org/bugs/show_bug.cgi?id=492212

Change-Id: Ib6bb6492e8b6f112c3f3ca32f5aaccb37cb263c8
Signed-off-by: Frank Becker <eclipse@frank-becker.de>
22 files changed