More than one file was found with OS independent path ‘META-INF/proguard/androidx-annotations.pro’

This is a known problem at the moment, Architecture Components Release Notes outline the issue and provides a solution to fix it until alpha10 version of work manager library:

Known Issue

If you run into the following issue: “More than one file was found with OS independent path ‘META-INF/proguard/androidx-annotations.pro'”, please put the following in your gradle file as a temporary workaround while we fix the issue in alpha10:

 android {
     packagingOptions {
         exclude 'META-INF/proguard/androidx-annotations.pro'
     }
 }

So, in your case, android section should be like following:

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "rock.dmx.xaro.workmanagerexample"
        minSdkVersion 19
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }

    // Temporary fix until alpha10
    packagingOptions {
        exclude 'META-INF/proguard/androidx-annotations.pro'
    }
}

Issue should be addressed properly in 1.0.0-alpha10 version of WorkManager.