[OPENENGSB-1722] Upgrad maven-plugin-plugin to 2.8
[OPENENGSB-1722] Upgrad maven-plugin-plugin to 2.8

Signed-off-by: Andreas Pieber <57efbcbb22ec0bd89955a40df26b44c340d3e38d@gmail.com>

GitHub2020/openengsb-root,openengsb/openengsb-root,openengsb/openengsb-root,GitHub2020/openengsb-root