upgrade asciidoctor dependencies

https://github.com/asciidoctor/asciidoctor-diagram/releases/tag/v2.2.6
updates PlantUML from 1.2022.14 to 1.2023.4.

Since plantuml-1.2023.2,
```
package com.myapp.application
```
produces 3 boxes instead of one by default.

cf. https://plantuml.com/news:
* 2 Feb, 2023: Important change about package and namespace
>
> Starting with version 1.2023.2 (which is online as a beta),
> PlantUML handles differently namespaces and packages.
>
> There won't be any difference between namespaces and packages anymore:
> both keywords are now synonymous.
>
> The drawing is slightly different, because we now also draw intermediate packages.
> Note that this is not a final choice, it depends on the feedback from users.
>
> Packages now involve the definition of a namespace, as in any ordinary programming language.
> The default separator is the dot (.) but can be changed using the `set separator X` directive.
> You can also disable namespace management using `set separator none`,
> in which case you get back a behavior similar to older versions of PlantUML.

Signed-off-by: Manfred Hanke <manfred.hanke@tngtech.com>

docs/build.gradle

@@ -24,7 +24,7 @@ asciidoctor {
     asciidoctorj {
         modules {
             diagram.use()
-            diagram.version '2.2.4'
+            diagram.version '2.2.14'  // https://github.com/asciidoctor/asciidoctorj-diagram/releases/
         }
     }
 }
@@ -34,7 +34,7 @@ asciidoctor.doFirst {
 }
 
 asciidoctorj {
-    version = '2.3.0'
+    version = '2.5.11'  // https://github.com/asciidoctor/asciidoctorj/releases
 }
 
 asciidoctor.dependsOn cleanUserGuide

docs/userguide/004_What_to_Check.adoc

@@ -86,6 +86,7 @@ classes().that().haveNameMatching(".*Bar")
 ----
 @startuml
 hide empty members
+set separator none
 skinparam componentStyle uml2
 
 skinparam component {
@@ -158,6 +159,7 @@ classes().that().implement(Connection.class)
 ----
 @startuml
 hide empty members
+set separator none
 skinparam componentStyle uml2
 
 skinparam component {
@@ -235,6 +237,7 @@ classes().that().areAssignableTo(EntityManager.class)
 ----
 @startuml
 hide empty members
+set separator none
 skinparam componentStyle uml2
 
 skinparam component {
@@ -292,6 +295,7 @@ layeredArchitecture()
 ----
 @startuml
 hide empty members
+set separator none
 skinparam componentStyle uml2
 
 skinparam component {

docs/userguide/008_The_Library_API.adoc

@@ -59,6 +59,7 @@ More precisely, the following holds:
 ----
 @startuml
 hide empty members
+set separator none
 skinparam componentStyle uml2
 
 skinparam class {