Disable composer memory limit & Add PHP 7.4 tests

Author: dmitry-ivanov

.travis.yml

@@ -3,6 +3,7 @@ language: php
 php:
   - 7.2
   - 7.3
+  - 7.4
 
 cache:
   directories:
@@ -15,8 +16,8 @@ before_install:
   - echo "extension = redis.so" >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini
 
 install:
-  - travis_retry composer install --no-interaction --prefer-dist
-  - travis_retry composer require --no-interaction --prefer-dist --dev php-coveralls/php-coveralls
+  - COMPOSER_MEMORY_LIMIT=-1 travis_retry composer install --no-interaction --prefer-dist
+  - COMPOSER_MEMORY_LIMIT=-1 travis_retry composer require --no-interaction --prefer-dist --dev php-coveralls/php-coveralls
 
 script: vendor/bin/phpunit --verbose --coverage-clover build/logs/clover.xml