Switch required bazel version to 0.29.1
Switch required bazel version to 0.29.1

Based on the corresponding core change series started with Ib48fdbb6.

Change-Id: I33e202e200639036ade96148b1b3e08e65978182

GerritCodeReview/plugins_serviceuser,GerritCodeReview/plugins_serviceuser,GerritCodeReview/plugins_serviceuser,GerritCodeReview/plugins_serviceuser,GerritCodeReview/plugins_serviceuser