Add rat check to build
diff --git a/pom.xml b/pom.xml
index 31af9ba..922bef4 100644
--- a/pom.xml
+++ b/pom.xml
@@ -94,6 +94,19 @@
   <build>
     <plugins>
       <plugin>
+        <groupId>org.apache.rat</groupId>
+        <artifactId>apache-rat-plugin</artifactId>
+        <version>0.12</version>
+        <executions>
+          <execution>
+            <phase>process-sources</phase>
+            <goals>
+              <goal>check</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
+      <plugin>
         <groupId>org.jetbrains.kotlin</groupId>
         <artifactId>kotlin-maven-plugin</artifactId>
         <version>${kotlin.version}</version>