update bash cmd

Author: CareF

packages/e2e/README.md

@@ -132,8 +132,9 @@ to set up a project.
 To run an e2e test on Android devices using Firebase Test Lab, use gradle commands to build an
 instrumentation test for Android, after creating `androidTest` as suggested in the last section.
 
-```
+```bash
 pushd android
+flutter build apk
 ./gradlew app:assembleAndroidTest
 ./gradlew app:assembleDebug -Ptarget=<path_to_test>.dart
 popd
@@ -142,7 +143,7 @@ popd
 Upload the build apks Firebase Test Lab, making sure to replace <PATH_TO_KEY_FILE>,
 <PROJECT_NAME>, <RESULTS_BUCKET>, and <RESULTS_DIRECTORY> with your values.
 
-```
+```bash
 gcloud auth activate-service-account --key-file=<PATH_TO_KEY_FILE>
 gcloud --quiet config set project <PROJECT_NAME>
 gcloud firebase test android run --type instrumentation \