> Task :copyLibraries FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':copyLibraries'.
> Could not resolve all files for configuration ':api'.
   > Could not find org.slf4j:slf4j-reload4j:${project.version}.
     Required by:
         project : > org.slf4j:slf4j-log4j12:1.7.34

plugins {
    id 'java-library'
}

repositories {
    mavenCentral()
}

configurations.api.setCanBeResolved(true)

dependencies {
    api group: 'org.slf4j', name: 'slf4j-api',      version: '1.7.+'
    api group: 'org.slf4j', name: 'slf4j-log4j12',  version: '1.7.+'
    api group: 'org.slf4j', name: 'jcl-over-slf4j', version: '1.7.+'
    api group: 'org.slf4j', name: 'jul-to-slf4j',   version: '1.7.+'
}

clean {
    delete "${rootDir}/lib"
}

task copyLibraries(type: Copy) {
    group = 'build'
    description = 'Copies libraries to the project\'s lib directory'
    from configurations.api + configurations.testCompileClasspath
    into 'lib'
}

gradle clean copyLibraries --refresh-dependencies --warning-mode all