cut a release with Java 8 support

[flavorjones]

See sparklemotion/nokogiri#2887 for the original reported issue. Using Nokogiri with nekodtd 0.1.11.noko1 on JRuby + Java 8 results in this error message:

java.lang.UnsupportedClassVersionError: org/cyberneko/dtd/DTDConfiguration has been compiled by a more recent version of the Java Runtime (class file version 55.0), this version of the Java Runtime only recognizes class file versions up to 52.0

In sparklemotion/nokogiri#2889 I demonstrated that recompiling nekodtd with Java 8 resulted in Nokogiri working on both Java 8 and Java 11.

So: let's build and release a new version of nekodtd compiled with Java 8 so that Nokogiri can cut a release with it.

[flavorjones]

Done: https://central.sonatype.com/artifact/org.nokogiri/nekodtd/0.1.11.noko2

See d19d5d8..7b26e8c and tag v0.1.11.noko2