配置freemarker（模板引擎）

<properties>
    <freemarker.version>2.3.23</freemarker.version>
</properties>

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.freemarker</groupId>
            <artifactId>freemarker</artifactId>
            <version>${freemarker.version}</version>
        </dependency>
    </dependencies>
</dependencyManagement>