Fix for mvn site command

[nyg]

Hello,

Small PR to fix the mvn site command which is failing with Maven 3.9.3.

The first error I had was:

SiteToolException: Error parsing site descriptor: TEXT must be immediately followed by END_TAG and not START_TAG (position: START_TAG seen ..."\n                src="http://www.google-analytics.com/urchin.js">... @16:65)

I fixed it by escaping both script tags in the head tag, see: https://stackoverflow.com/questions/67315542/mvn-site-plugin-error-text-must-be-immediately-followed-by-end-tag-and-not-start.

The second error was related to a breaking change in the configuration of maven-antrun-plugin, tasks should be replaced by target, see: https://maven.apache.org/plugins/maven-antrun-plugin/.

You are using 'tasks' which has been removed from the maven-antrun-plugin. Please use 'target' and refer to the >>Major Version Upgrade to version 3.0.0<< on the plugin site.

Now the command succeeds but there is still an issue with maven-javadoc-plugin, fixed by upgrading the plugin to version 3.5.0.

[WARNING] An issue has occurred with maven-javadoc-plugin:3.4.0:aggregate-no-fork report, skipping LinkageError org.apache.maven.plugins.javadoc.AggregatorJavadocNoForkReport.generate(Lorg/codehaus/doxia/sink/Sink;Ljava/util/Locale;)V, please report an issue to Maven dev team.

Let me know if I've missed anything.
nyg