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

Change-Id: I4a4655e69eccc2e9ac3353891e058c5ad898c971
Task-Url: https://bugs.eclipse.org/bugs/show_bug.cgi?id=492212
Signed-off-by: Frank Becker <eclipse@frank-becker.de>
8 files changed