Upgrade sortpom-maven-plugin 3.1.3 -> 3.2.0 (#157)

See:
- https://github.com/Ekryd/sortpom/wiki/Versions
- https://github.com/Ekryd/sortpom/releases/tag/sortpom-parent-3.2.0
- Ekryd/sortpom@sortpom-parent-3.1.3...sortpom-parent-3.2.0

pom.xml

@@ -398,7 +398,7 @@
                 <plugin>
                     <groupId>com.github.ekryd.sortpom</groupId>
                     <artifactId>sortpom-maven-plugin</artifactId>
-                    <version>3.1.3</version>
+                    <version>3.2.0</version>
                     <configuration>
                         <createBackupFile>false</createBackupFile>
                         <encoding>${project.build.sourceEncoding}</encoding>