Added .travis.yml

Author: slavvka

.travis.yml

@@ -0,0 +1,15 @@
+language: php
+
+php:
+  - '7.1'
+  - '7.2'
+  - '7.3'
+
+matrix:
+  fast_finish: true
+
+before_install:
+  - travis_retry composer self-update
+  - composer install --prefer-source --no-interaction --dev
+
+script: php vendor/phpunit/phpunit/phpunit --configuration tests/Unit/phpunit.xml.dist