lowest build and remove hhvm

Author: dbu

.travis.yml

@@ -22,10 +22,8 @@ branches:
 matrix:
     fast_finish: true
     include:
-        - php: 5.5
+        - php: 7.1
           env: COMPOSER_FLAGS="--prefer-stable --prefer-lowest" COVERAGE=true TEST_COMMAND="composer test-ci"
-        - php: hhvm
-          dist: trusty
 
 before_install:
     - if [[ $COVERAGE != true ]]; then phpenv config-rm xdebug.ini || true; fi