kiji-express: [maven-release-plugin] prepare for next development iteration

commit: https://github.com/kijiproject/kiji-express/commit/cd2a9bfb4e7221642257ac75154d0284b14ab678
kiji-express: [maven-release-plugin] prepare release kiji-express-0.13.0

commit: https://github.com/kijiproject/kiji-express/commit/98bd99a267eaed3f5b64f28bd0ddfc7f7c3607fa