fixup: correct details markdown for dependency metadata

[lemeurherve]

This PR sets the text value of the check run, using <pre>, 
 (new line) and < (<) to avoid markdown rendering issue from #83: https://github.com/jenkinsci/jenkins-infra-test-plugin/pull/114/checks?check_run_id=21437296074

Before:

After:

<pre>&#xA;&#60;dependency>&#xA;  &#60;groupId>${entries[0].groupId}&#60;/groupId>&#xA;  &#60;artifactId>${entries[0].artifactId}&#60;/artifactId>&#xA;  &#60;version>${entries[0].version}&#60;/version>&#xA;&#60;/dependency>&#xA;</pre>

<dependency>
  <groupId>${entries[0].groupId}</groupId>
  <artifactId>${entries[0].artifactId}</artifactId>
  <version>${entries[0].version}</version>
</dependency>

Fixup of:

• feat: show dependency metadata in check summary #83

Ref:

• Show dependency metadata in the GitHub check #22
• https://docs.github.com/en/rest/checks/runs?apiVersion=2022-11-28