Github CI: Build with JDK 15, test with matrix
Github CI: Build with JDK 15, test with matrix

Signed-off-by: Markus KARG <300a2d193222dd0c23d880e16d727d352b404a01@headcrashing.eu>

codehaus-plexus/plexus-utils,codehaus-plexus/plexus-utils,codehaus-plexus/plexus-utils