Revert "Merge pull request #64 from jenkinsci/dependabot/maven/org.co…

…dehaus.mojo-versions-maven-plugin-2.16.0"

This reverts commit 00066a8, reversing
changes made to c83b4d8.

maven-plugin/pom.xml

@@ -26,7 +26,7 @@
         <dependency>
             <groupId>org.codehaus.mojo</groupId>
             <artifactId>versions-maven-plugin</artifactId>
-            <version>2.16.0</version>
+            <version>2.15.0</version>
         </dependency>
         <dependency>
             <groupId>org.apache.maven.plugin-tools</groupId>