Update Travis CI PHP versions

Author: filips123

.travis.yml

@@ -1,4 +1,5 @@
 language: php
+dist: trusty
 
 php:
   - 5.5
@@ -26,7 +27,7 @@ script:
 
 after_script:
   - |
-    if [[ ${TRAVIS_PHP_VERSION:0:3} == "7.2" ]]
+    if [[ ${TRAVIS_PHP_VERSION:0:3} == "7.3" ]]
     then
       travis_retry wget --no-verbose https://scrutinizer-ci.com/ocular.phar
       php ocular.phar code-coverage:upload --format=php-clover build/clover.xml