[eclipse/xtext-umbrella#65] Adjust upstream branch
[eclipse/xtext-umbrella#65] Adjust upstream branch

Added property ‚upstreamBranch‘ which is considered by adjustPipelines.sh script

Signed-off-by: Karsten Thoms <dec0ef9b050f1aa68d12b8ac7c21dd1e6ea132c8@itemis.de>

miklossy/xtext-core,miklossy/xtext-core