Upgrade maven-source-plugin to 3.2.1

Change-Id: I344241362bae736293b871715351e3281ef5d937

pom.xml

diff --git a/pom.xml b/pom.xml
index 9fdf2ce..28ed991 100644
--- a/pom.xml
+++ b/pom.xml
@@ -407,7 +407,7 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-source-plugin</artifactId>
-        <version>3.0.1</version>
+        <version>3.2.1</version>
         <executions>
           <execution>
             <goals>