Update .travis.yml and remove unused variable from the ExpoChannel

Author: Alymosul

.travis.yml

@@ -4,14 +4,9 @@ php:
   - 7.0
   - 7.1
 
-env:
-  matrix:
-    - COMPOSER_FLAGS="--prefer-lowest"
-    - COMPOSER_FLAGS=""
-
 before_script:
   - travis_retry composer self-update
-  - travis_retry composer update ${COMPOSER_FLAGS} --no-interaction --prefer-source
+  - travis_retry composer update --no-interaction --prefer-source
 
 script:
   - phpunit --coverage-text --coverage-clover=coverage.clover

src/ExpoChannel.php

@@ -49,7 +49,7 @@ public function send($notifiable, Notification $notification)
             ?: $this->interestName($notifiable);
 
         try {
-            $response = $this->expo->notify(
+            $this->expo->notify(
                 $interest,
                 $notification->toExpoPush($notifiable)->toArray(),
                 true