Merge pull request #771 from jmp/upgrade-asciidoctorj-to-v2.5.7

Fix java.lang.UnsatisfiedLinkError thrown on Apple M1

Author: jonbullock

gradle.properties

@@ -7,7 +7,7 @@ issues                      = https://github.com/jbake-org/jbake/issues
 vcs                         = https://github.com/jbake-org/jbake/
 
 # runtime dependencies
-asciidoctorjVersion         = 2.5.2
+asciidoctorjVersion         = 2.5.7
 asciidoctorjDiagramVersion  = 2.2.1
 args4jVersion               = 2.33
 commonsIoVersion            = 2.11.0