Remove support for old version of php

Author: joelwurtz

.travis.yml

@@ -7,9 +7,6 @@ cache:
         - $HOME/.composer/cache
 
 php:
-    - 5.5
-    - 5.6
-    - 7.0
     - 7.1
     - 7.2
     - 7.3
@@ -23,15 +20,10 @@ branches:
         - /^analysis-.*$/
 
 matrix:
-    allow_failures:
-        - php: hhvm
-          dist: trusty
     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:
     - travis_retry composer self-update

composer.json

@@ -9,7 +9,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^7.1",
         "symfony/options-resolver": "^2.6 || ^3.0 || ^4.0",
         "php-http/httplug": "^1.0",
         "php-http/message-factory": "^1.0.2",