kiji-mapreduce: [maven-release-plugin] prepare release kiji-mapreduce-root-1.2.8

commit: https://github.com/kijiproject/kiji-mapreduce/commit/e401d17eaa85051be79e5e320d26f4822fa4f035
kiji-mapreduce: [maven-release-plugin] prepare for next development iteration

commit: https://github.com/kijiproject/kiji-mapreduce/commit/efe2ae247c060ceee72dd382cfc6838db3797735