Update dependencies and travis config

Author: Matthijs van Dorp

.travis.yml

@@ -2,10 +2,9 @@ language: php
 sudo: false
 
 php:
-  - 5.4
-  - 5.5
-  - 5.6
-  - hhvm
+  - 7.1
+  - 7.2
+  - 7.3
 
 before_script:
   - composer install --dev

composer.json

@@ -11,12 +11,12 @@
     ],
     "require": {
         "php": ">=5.4.0",
-        "illuminate/support": "5.x"
+        "illuminate/support": "^5.8"
     },
     "require-dev": {
-        "mockery/mockery": "~0.9.4",
-        "orchestra/testbench": "3.0.*",
-        "phpunit/phpunit": "3.7.*"
+        "mockery/mockery": "~1.0",
+        "orchestra/testbench": "3.8.*",
+        "phpunit/phpunit": "^7.5"
     },
     "autoload": {
         "psr-4": {