Bump asciidoctorj from 2.5.6 to 2.5.7 (#62)

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

pom.xml

@@ -37,7 +37,7 @@
 
     <nexus-staging-maven-plugin.version>1.6.13</nexus-staging-maven-plugin.version>
     <!-- Documentation -->
-    <asciidoctorj.version>2.5.6</asciidoctorj.version>
+    <asciidoctorj.version>2.5.7</asciidoctorj.version>
     <asciidoctor-maven-plugin.version>2.2.2</asciidoctor-maven-plugin.version>
     <yaml-properties-maven-plugin.version>1.1.3</yaml-properties-maven-plugin.version>
   </properties>