Give examples of adding methods to interfaces as incompatible (#1503)
Give examples of adding methods to interfaces as incompatible (#1503)

* Give examples of adding methods to interfaces as incompatible

@suztomo since this is one of the cases we see most frequently

* Update JLBP-0003.md
GoogleCloudPlatform/cloud-opensource-java,GoogleCloudPlatform/cloud-opensource-java,GoogleCloudPlatform/cloud-opensource-java