You need to make sure you add a filter. Below config works file for me.
<build>
<filters>
<filter>your filter file here</filter>
</filters>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<executions>
<execution>
<goals>
<goal>war</goal>
</goals>
<configuration>
<warSourceDirectory>src/main/webapp</warSourceDirectory>
<webResources>
<resource>
<directory>src/main/webapp</directory>
<filtering>true</filtering>
<includes>
<include>**/*.xml</include>
</includes>
</resource>
</webResources>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
