Use android docker image on circleci

.circleci/config.yml

@@ -2,7 +2,7 @@ version: 2
 jobs:
   build:
     machine:
-      image: circleci/classic:latest
+      image: stefma-docker-hub.bintray.io/android-build-env:0.2-alpha
 
     environment:
       # Customize the JVM maximum heap limit
@@ -15,15 +15,6 @@ jobs:
       # Set the JVM heap size to gradle as well
       - run: echo "org.gradle.jvmargs=-Xmx2G" >> gradle.properties
 
-      # Download/Install Android SDK for testing
-      - run: wget -q https://dl.google.com/android/repository/sdk-tools-linux-3859397.zip
-      - run: unzip -q sdk-tools-linux-3859397.zip
-      - run: mkdir $HOME/android-sdk
-      - run: mv tools $HOME/android-sdk/tools
-      - run: mkdir $HOME/android-sdk/licenses
-      - run: echo -e "\nd56f5187479451eabf01fb78af6dfcb131a6481e" > "$HOME/android-sdk/licenses/android-sdk-license"
-      - run: echo -e "\n84831b9409646a918e30573bab4c9c91346d8abd" > "$HOME/android-sdk/licenses/android-sdk-preview-license"
-
       # Try to restore cache (see ho to save cache below 👇)
       - restore_cache:
           key: gradle-cache-v0-{{ checksum "build.gradle" }}-{{ checksum "core/build.gradle" }}-{{ checksum "gradle/wrapper/gradle-wrapper.properties" }}