IcuCodeTools: update field when there are commits

[srl295]

when a commit happens, update a custom field so that queries can determine whether there are commits/etc.

Perhaps, a read-only (to users) space-separated field with contents such as:

icu4j/trunk icu/branches/srl/foo icuhtml/trunk
Ideas:

I'm not sure what format will be the most friendly for queries. Perhaps it would be better to have multiple fields, such as one for trunk and one for branch? or one for icu4c and one for icu4j?

……

• go with a single field

[srl295]

from http://bugs.icu-project.org/trac/ticket/11350#comment:4