ksgen/test: updates env test data file

Change-Id: Id4d88d003ed9c56a974b6e86a237cc3a240252f6
(cherry picked from commit cd78335b31e153ba60f9c77038928b85d00bcf39)
ksgen/readme: adds doc about yaml tags

Change-Id: Iedec9d0ed605922b5cd82d21a1d066b3395f6fef
(cherry picked from commit b296378641586e8ca9162540508bdab0f8eed494)