Bump dom4j from 2.1.1 to 2.1.3 in /rets-io-client

Bumps [dom4j](https://github.com/dom4j/dom4j) from 2.1.1 to 2.1.3.
- [Release notes](https://github.com/dom4j/dom4j/releases)
- [Commits](https://github.com/dom4j/dom4j/compare/version-2.1.1...version-2.1.3)

---
updated-dependencies:
- dependency-name: org.dom4j:dom4j
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

rets-io-client/pom.xml

@@ -85,7 +85,7 @@
         <dependency>
             <groupId>org.dom4j</groupId>
             <artifactId>dom4j</artifactId>
-            <version>2.1.1</version>
+            <version>2.1.3</version>
         </dependency>
         <dependency>
             <groupId>xalan</groupId>