Bring optional p2 update sites up to date

The simrel and cdt update sites can be used to run partial builds
and are not used by default when doing builds. This change
brings those URLs up to date.

pom.xml

@@ -25,8 +25,8 @@
 		<tycho-version>4.0.6</tycho-version>
 		<cbi-plugins.version>1.4.3</cbi-plugins.version>
 		<sonar.core.codeCoveragePlugin>jacoco</sonar.core.codeCoveragePlugin>
-		<cdt-site>http://ci.eclipse.org/cdt/job/cdt-master/lastSuccessfulBuild/artifact/releng/org.eclipse.cdt.repo/target/repository</cdt-site>
-		<simrel-site>https://download.eclipse.org/staging/2023-12/</simrel-site>
+		<cdt-site>https://ci.eclipse.org/cdt/job/cdt/job/main/lastSuccessfulBuild/artifact/releng/org.eclipse.cdt.repo/target/repository</cdt-site>
+		<simrel-site>https://download.eclipse.org/staging/2024-06/</simrel-site>
 		<repo-path>tools/cdt/builds/master/nightly</repo-path>
 		<sonar.dynamicAnalysis>reuseReports</sonar.dynamicAnalysis>
 		<sonar.jacoco.reportPath>${project.basedir}/../../target/jacoco.exec</sonar.jacoco.reportPath>