[OPENENGSB-1296] Upgrade maven-plugin-api to 3.0.3
[OPENENGSB-1296] Upgrade maven-plugin-api to 3.0.3

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

openengsb-attic/openengsb-maven-plugin