Update required JDK version to JDK8
Update required JDK version to JDK8

Fixes gh-4154.

spring-projects/spring-security,olezhuravlev/spring-security,wkorando/spring-security,djechelon/spring-security,kazuki43zoo/spring-security,djechelon/spring-security,kazuki43zoo/spring-security,thomasdarimont/spring-security,pwheel/spring-security,fhanik/spring-security,pwheel/spring-security,kazuki43zoo/spring-security,rwinch/spring-security,rwinch/spring-security,djechelon/spring-security,olezhuravlev/spring-security,rwinch/spring-security,pwheel/spring-security,fhanik/spring-security,thomasdarimont/spring-security,eddumelendez/spring-security,thomasdarimont/spring-security,kazuki43zoo/spring-security,eddumelendez/spring-security,rwinch/spring-security,olezhuravlev/spring-security,spring-projects/spring-security,eddumelendez/spring-security,djechelon/spring-security,spring-projects/spring-security,fhanik/spring-security,olezhuravlev/spring-security,spring-projects/spring-security,jgrandja/spring-security,jgrandja/spring-security,jgrandja/spring-security,pwheel/spring-security,eddumelendez/spring-security,rwinch/spring-security,thomasdarimont/spring-security,pwheel/spring-security,fhanik/spring-security,olezhuravlev/spring-security,thomasdarimont/spring-security,jgrandja/spring-security,fhanik/spring-security,eddumelendez/spring-security,fhanik/spring-security,wkorando/spring-security,rwinch/spring-security,djechelon/spring-security,wkorando/spring-security,spring-projects/spring-security,spring-projects/spring-security,spring-projects/spring-security,jgrandja/spring-security,wkorando/spring-security,jgrandja/spring-security,kazuki43zoo/spring-security