Update .travis.yml

Author: voku

.travis.yml

@@ -37,6 +37,10 @@ matrix:
     env: extension='true'
   - php: 7.2
     env: extension='false'
+  - php: 7.3
+    env: extension='true'
+  - php: 7.3
+    env: extension='false'
 
 before_script:
 - php --version
@@ -62,4 +66,4 @@ script:
 after_script:
 - php vendor/bin/coveralls -v
 - php ocular.phar code-coverage:upload --format=php-clover build/logs/clover.xml
-- bash <(curl -s https://codecov.io/bash)
+- bash <(curl -s https://codecov.io/bash)