Bump maven-source-plugin from 2.2.1 to 3.1.0

Bumps [maven-source-plugin](https://github.com/apache/maven-source-plugin) from 2.2.1 to 3.1.0.
- [Release notes](https://github.com/apache/maven-source-plugin/releases)
- [Commits](apache/maven-source-plugin@maven-source-plugin-2.2.1...maven-source-plugin-3.1.0)

Author: dependabot-preview[bot]

pom.xml

@@ -85,7 +85,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-source-plugin</artifactId>
-                <version>2.2.1</version>
+                <version>3.1.0</version>
                 <executions>
                     <execution>
                         <id>attach-sources</id>
@@ -186,7 +186,7 @@
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>
                     <artifactId>maven-source-plugin</artifactId>
-                    <version>2.2.1</version>
+                    <version>3.1.0</version>
                     <executions>
                         <execution>
                             <id>attach-sources</id>