chore(deps): update dependency org.apache.maven.plugins:maven-source-plugin to v3.2.1 (googleapis#1459)

Author: renovate-bot

pom.xml

@@ -253,7 +253,7 @@
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-source-plugin</artifactId>
-          <version>3.2.0</version>
+          <version>3.2.1</version>
           <executions>
             <execution>
               <id>attach-sources</id>