[build] Update to Apache Maven PMD Plugin 3.5

http://maven.apache.org/plugins/maven-pmd-plugin/

You should specify the version in your project's plugin configuration:

```xml
<plugin>
 <groupId>org.apache.maven.plugins</groupId>
 <artifactId>maven-pmd-plugin</artifactId>
 <version>3.5</version>
</plugin>
```

Release Notes - Apache Maven PMD Plugin - Version 3.5
---------------

Bug

* [MPMD-208] Warning about deprecated Rule name when using rulesets/maven.xml
* [MPMD-205] Javascript violations won't fail the build

Improvement

* [MPMD-211] Upgrade plexus-resources from 1.0-alpha-7 to 1.1
* [MPMD-209] Upgrade to PMD 5.3.2
* [MPMD-206] Make the sourceDirectories configurable

New Feature

* [MPMD-207] Support Javascript and JSP for CPD

pom.xml

@@ -1104,7 +1104,7 @@ org.eclipse.jdt.ui.text.custom_code_templates=<?xml version\="1.0" encoding\="UT
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>
                     <artifactId>maven-pmd-plugin</artifactId>
-                    <version>3.3</version>
+                    <version>3.5</version>
                     <configuration>
                         <rulesets>
                             <ruleset>${elasticsearch.tools.directory}/pmd/custom.xml</ruleset>