Generate mvn pom for ssl-config library

This is used by the reindex-client library which is published to maven

Relates: elastic#37287, elastic#37527
Backport of: elastic#39019

Author: tvernum

libs/ssl-config/build.gradle

@@ -17,6 +17,9 @@
  * under the License.
  */
 
+apply plugin: 'nebula.maven-base-publish'
+apply plugin: 'nebula.maven-scm'
+
 dependencies {
     compile "org.elasticsearch:elasticsearch-core:${version}"