Bump doxiaVersion from 1.12.0 to 2.0.0

Bumps `doxiaVersion` from 1.12.0 to 2.0.0.

Updates `org.apache.maven.doxia:doxia-core` from 1.12.0 to 2.0.0
- [Release notes](https://github.com/apache/maven-doxia/releases)
- [Commits](apache/maven-doxia@doxia-1.12.0...doxia-2.0.0)

Updates `org.apache.maven.doxia:doxia-sink-api` from 1.12.0 to 2.0.0
- [Release notes](https://github.com/apache/maven-doxia/releases)
- [Commits](apache/maven-doxia@doxia-1.12.0...doxia-2.0.0)

---
updated-dependencies:
- dependency-name: org.apache.maven.doxia:doxia-core
  dependency-type: direct:production
  update-type: version-update:semver-major
- dependency-name: org.apache.maven.doxia:doxia-sink-api
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

pom.xml

@@ -123,7 +123,7 @@
 
     <processorVersion>1.3</processorVersion>
 
-    <doxiaVersion>1.12.0</doxiaVersion>
+    <doxiaVersion>2.0.0</doxiaVersion>
     <!-- ASF project maven-doxia-sitetools:1.8.1 has different release cycle and it is dependent on maven-doxia:1.8 -->
     <doxiaRendererVersion>1.11.1</doxiaRendererVersion>