Update pom.xml

using jruby-core means that maven tries to find a new version of com.github.jnr:jffi:jar:native and com.github.jnr:jnr-x86asm:jar daily (which I do see with nexus-ruby-support). maven does not have a "lock-down" mechanism as bundler has, that is why maven discourages the use of version ranges. for a reproducible build/project you need to fix the version as I did with that patch.

maven always allows to overwrite that version in your main pom by just declaring the artifact there.

thanx,
christian