Add Travis-ci retry for long running tasks

Author: moux2003

.travis.yml

@@ -44,8 +44,8 @@ before_install:
 
 install:
     # To be removed when this issue will be resolved: https://github.com/composer/composer/issues/5355
-    - if [[ "$COMPOSER_FLAGS" == *"--prefer-lowest"* ]]; then composer update --prefer-dist --no-interaction --prefer-stable --quiet; fi
-    - composer update ${COMPOSER_FLAGS} --prefer-dist --no-interaction
+    - if [[ "$COMPOSER_FLAGS" == *"--prefer-lowest"* ]]; then travis_retry composer update --prefer-dist --no-interaction --prefer-stable --quiet; fi
+    - travis_retry composer update ${COMPOSER_FLAGS} --prefer-dist --no-interaction
     - ./vendor/bin/simple-phpunit install
 
 script: