Update nexus-staging-maven-plugin to 1.6.13

This will fix the issue `An API incompatibility was encountered while executing org.sonatype.plugins:nexus-staging-maven-plugin:1.6.7:deploy`

Author: ziyanli-amazon

pom.xml

@@ -142,7 +142,7 @@
       <plugin>
         <groupId>org.sonatype.plugins</groupId>
         <artifactId>nexus-staging-maven-plugin</artifactId>
-        <version>1.6.7</version>
+        <version>1.6.13</version>
         <extensions>true</extensions>
         <configuration>
           <serverId>ossrh</serverId>