Support PHP 7.2+ only (#10)

Author: webignition

.travis.yml

@@ -1,14 +1,15 @@
 sudo: false
 language: php
 php:
-  - 5.6
-  - 7
-  - 7.1
-  - 7.2
+- 7.2
 
 install:
-  - composer install
+- composer install --prefer-dist
 
 script:
-  - composer cs
-  - composer test
+- composer cs
+- composer test
+
+cache:
+  directories:
+  - $HOME/.composer/cache/files

circle.yml

@@ -30,15 +30,15 @@
         ]
     },
     "require": {
-        "php": ">=5.6.0",
-        "webignition/internet-media-type-interface":">=0.1,<1.0",
+        "php": ">=7.2.0",
+        "webignition/internet-media-type-interface":">=0.4,<1.0",
         "webignition/quoted-string":">=0.2.1,<1.0",
         "webignition/string-parser":">=0.2.3,<1.0"
 
     },
     "require-dev": {
-        "phpunit/phpunit": "~5.0",
-        "squizlabs/php_codesniffer": "3.*"
+        "phpunit/phpunit": "^7",
+        "squizlabs/php_codesniffer": "^3"
     },
     "minimum-stability":"stable",
     "prefer-stable":true