[maven-release-plugin] prepare release 0.20.0
[maven-release-plugin] prepare release 0.20.0

codenvy/codenvy,R-Brain/codenvy,R-Brain/codenvy,codenvy/codenvy,R-Brain/codenvy,codenvy/codenvy,codenvy/codenvy,R-Brain/codenvy,codenvy/codenvy,R-Brain/codenvy,R-Brain/codenvy,codenvy/codenvy