Bump maven-source-plugin from 2.3 to 3.1.0

Bumps [maven-source-plugin](https://github.com/apache/maven-source-plugin) from 2.3 to 3.1.0.
- [Release notes](https://github.com/apache/maven-source-plugin/releases)
- [Commits](apache/maven-source-plugin@maven-source-plugin-2.3...maven-source-plugin-3.1.0)

pom.xml

@@ -113,7 +113,7 @@
         <apacheds.version>1.5.7</apacheds.version>
         <system-rules.version>1.16.0</system-rules.version>
         <maven-javadoc-plugin.version>2.9.1</maven-javadoc-plugin.version>
-        <maven-source-plugin.version>2.3</maven-source-plugin.version>
+        <maven-source-plugin.version>3.1.0</maven-source-plugin.version>
         <maven-gpg-plugin.version>1.5</maven-gpg-plugin.version>
         <maven-compiler-plugin.version>3.1</maven-compiler-plugin.version>
         <maven-resources-plugin.version>2.6</maven-resources-plugin.version>