Update dependency org.jenkins-ci.plugins:plugin to v6 (#1110)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

pom.xml

@@ -4,7 +4,7 @@
   <parent>
     <groupId>org.jenkins-ci.plugins</groupId>
     <artifactId>plugin</artifactId>
-    <version>5.2102.v5f5fe09fccf1</version>
+    <version>6.2108.v08c2b_01b_cf4d</version>
     <relativePath />
   </parent>