Bye bye HHVM

HHVM is not compatible with Symfony4 and it is no longer worth the hassle

.travis.yml

@@ -6,16 +6,11 @@ php:
   - 7.1
   - 7.2
   - 7.3
-  - hhvm
 
 env:
   - COMMAND="install"
   - COMMAND="update"
 
-matrix:
-  allow_failures:
-    - php: hhvm
-
 before_script:
   - composer ${COMMAND}
   - if [[ "$TRAVIS_PHP_VERSION" == "7.3" ]]; then composer require --dev vimeo/psalm:0.3.92; fi