Update dependency io.jenkins.tools.bom:bom-2.541.x to v6421

Author: renovate[bot]

pom.xml

@@ -42,7 +42,7 @@
     <jenkins.baseline>2.541</jenkins.baseline>
     <jenkins.version>${jenkins.baseline}.1</jenkins.version>
     <tagNameFormat>configuration-as-code-@{project.version}</tagNameFormat>
-    <plugin-bom.version>6269.v7a_159d68a_366</plugin-bom.version>
+    <plugin-bom.version>6421.v4a_efb_4b_3a_61d</plugin-bom.version>
     <spotless.check.skip>false</spotless.check.skip>
   </properties>