<dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.eclipse.xtext</groupId>
                <artifactId>xtext-dev-bom</artifactId>
                <version>${xtextVersion}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        ...
        classpath 'io.spring.gradle:dependency-management-plugin:1.0.6.RELEASE'
    }
}

subprojects {
...
    apply plugin: 'io.spring.dependency-management'
    dependencyManagement {
        imports {
            mavenBom "org.eclipse.xtext:xtext-dev-bom:2.17.0.M1"
        }
    }
...
}

    dependencies {
        compile platform("org.eclipse.xtext:xtext-dev-bom:2.17.0.M1")
    }