jenkinsci/testng-plugin-plugin — pull request #14 by jglick (2014-08-08 15:41:12+00:00)
Title: Removing gratuitous dependency on maven-plugin.

Looks like https://github.com/jenkinsci/testng-plugin-plugin/commit/a9b873e6f0d3106f3567ef8ac711f2d6eb32105c (over three years ago!) forgot to remove the POM dependency, and thus the plugin dependency.