Revert "[maven-release-plugin] prepare for next development iteration"

This reverts commit dad7e0dd52eabc6d1ee53664ebe318b912edd802.
Revert "[maven-release-plugin] prepare release v0.8.0-incubating"

This reverts commit 32fc25093e0be2c99a5b14f1678bb838ccb18518.