Update Sonatype OSS parent pom.xml version

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Fix Maven warnings: specify all plugin versions

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Specify GitHub as issue management tool in pom.xml

[ci skip]

Signed-off-by: Alex Coles <alex@alexbcoles.com>