bring back "integration" testing #262

Job	Run time
JRuby 9.4.13.0 / Java 11	1m 7s
JRuby 9.4.13.0 / Java 17	1m 12s
JRuby 9.4.13.0 / Java 21	1m 8s
JRuby 10.0.1.0 / Java 21	1m 23s
${{ matrix.appraisal }} appraisal on ${{ matrix.jruby_version }} / Java ${{ matrix.java_version }}	-1s
	4m 49s

Provide feedback