Introduce --dry-run mode for release-version.sh

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Adapt release-version.sh to nar-maven-plugin living on OSS Sonatype

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Fix tyop

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>