Also test against PHP 7.3

Author: JeroenDeDauw

.travis.yml

@@ -5,6 +5,7 @@ dist: trusty
 php:
   - 7.1
   - 7.2
+  - 7.3
   - master
 
 sudo: false
@@ -18,7 +19,7 @@ script:
   - if [[ "`phpenv version-name`" == "7.1" ]]; then composer cs; fi
 
 after_success:
-  - if [[ "`phpenv version-name`" != "7.2" ]]; then exit 0; fi
+  - if [[ "`phpenv version-name`" != "7.3" ]]; then exit 0; fi
   - vendor/bin/phpunit --coverage-clover coverage.clover
   - wget https://scrutinizer-ci.com/ocular.phar
   - php ocular.phar code-coverage:upload --format=php-clover coverage.clover