Apply spotless re-formatting

Detected in the course of support-and-care/maven-support-and-care#77.

Author: ascheman

README.md

@@ -1,5 +1,5 @@
 Plexus-Xml
-============
+==========
 
 [![Build Status](https://github.com/codehaus-plexus/plexus-xml/actions/workflows/maven.yml/badge.svg)](https://github.com/codehaus-plexus/plexus-xml/actions)
 [![Maven Central](https://img.shields.io/maven-central/v/org.codehaus.plexus/plexus-xml.svg?label=Maven%20Central&versionPrefix=3.)](https://search.maven.org/artifact/org.codehaus.plexus/plexus-xml)
@@ -22,3 +22,4 @@ For publishing [the site](https://codehaus-plexus.github.io/plexus-xml/) do the
 ```
 mvn -Preporting verify site site:stage scm-publish:publish-scm
 ```
+