title: RecyclerView and CardView don't support compileSdkVersion
body: <p>recently I implemented <code>RecyclerView</code> and <code>CardView</code> in gradle file but the version of both of them doesn't match the <code>compileSdkVersion</code> this is my build.gradle file:</p>
  
  <pre><code>android {
      compileSdkVersion 26
      defaultConfig {
          applicationId "com.example.mostafa.tostrategies"
          minSdkVersion 24
          targetSdkVersion 26
          versionCode 1
          versionName "1.0"
          testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
      }
      buildTypes {
          release {
              minifyEnabled false
              proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
          }
      }
      dependencies {
      implementation fileTree(include: ['*.jar'], dir: 'libs')
      implementation 'com.android.support:appcompat-v7:26.1.0'
      implementation 'com.android.support.constraint:constraint-layout:1.0.2'
      testImplementation 'junit:junit:4.12'
      androidTestImplementation 'com.android.support.test:runner:1.0.1'
      androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
      implementation 'com.android.support:cardview-v7:28.0.0-alpha1'
      implementation 'com.android.support:recyclerview-v7:28.0.0-alpha1'
  
  }
  </code></pre>