update travis & version constraints

Author: clarkeash

.travis.yml

@@ -25,11 +25,11 @@ cache:
 before_install:
 - travis_retry composer self-update
 - composer require "illuminate/contracts:5.${ILLUMINATE_MINOR_VERSION}.*" --no-update
-- composer require "orchestra/testbench:3.${ILLUMINATE_MINOR_VERSION}.*" --dev --no-update
-- composer require "phpunit/phpunit:^${PHP_UNIT}" --dev --no-update
+- composer require "orchestra/testbench:3.${ILLUMINATE_MINOR_VERSION}.*" --no-update
+- composer require "phpunit/phpunit:^${PHP_UNIT}" --no-update
 
 install:
-- travis_retry composer update --prefer-source --no-interaction --no-suggest --dev
+- travis_retry composer update --prefer-source --no-interaction --no-suggest
 
 script:
 - vendor/bin/phpunit --coverage-text --coverage-clover=coverage.clover

composer.json

@@ -10,11 +10,11 @@
         }
     ],
     "require": {
-        "illuminate/contracts": "^5.6"
+        "illuminate/contracts": "^5.5"
     },
     "require-dev": {
-        "orchestra/testbench": "^3.6",
-        "phpunit/phpunit": "^7.0"
+        "orchestra/testbench": "^3.5",
+        "phpunit/phpunit": "^6.0|^7.0"
     },
     "autoload": {
         "psr-4": {