[KARAF-7351] Upgrade to asciidoctor-maven-plugin 2.2.1
diff --git a/manual/pom.xml b/manual/pom.xml
index 9971e3b..c86e6bf 100644
--- a/manual/pom.xml
+++ b/manual/pom.xml
@@ -38,7 +38,7 @@
             <plugin>
                 <groupId>org.asciidoctor</groupId>
                 <artifactId>asciidoctor-maven-plugin</artifactId>
-                <version>1.5.6</version>
+                <version>2.2.1</version>
                 <executions>
                     <execution>
                         <id>output-html</id>