<NME> build.gradle
<BEF> apply plugin: 'com.android.application'

android {
    compileSdkVersion 26
    buildToolsVersion '26.0.2'

    defaultConfig {
        versionCode 1
        versionName '1.0'
        minSdkVersion 9
        targetSdkVersion 26

        proguardFiles getDefaultProguardFile('proguard-android.txt')
    }

    // We're enabling proguard just to prove we don't have to do anything
    // special to get this build to work with proguard.
    buildTypes {
        debug {
            minifyEnabled true
            shrinkResources true
        }
    }

    lintOptions {
        // We don't care THAT much about lint issues with our sample
        abortOnError false
    }
}

repositories {
    mavenCentral()
}

    implementation project(':library')

    androidTestImplementation libs.junit
    androidTestImplementation libs.androidx.test.runner
    androidTestImplementation libs.androidx.test.ext.junit
}

<MSG> Updated dependencies and build targets

<DFF> @@ -1,14 +1,14 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 26
-    buildToolsVersion '26.0.2'
+    compileSdkVersion 27
+    buildToolsVersion '27.0.3'
 
     defaultConfig {
         versionCode 1
         versionName '1.0'
         minSdkVersion 9
-        targetSdkVersion 26
+        targetSdkVersion 27
 
         proguardFiles getDefaultProguardFile('proguard-android.txt')
     }
@@ -29,6 +29,8 @@ android {
 }
 
 repositories {
+    google()
+    jcenter()
     mavenCentral()
 }
 

Updated dependencies and build targets