Fix composer.json minimum php version, and make coveralls a dev dependency

Author: Jaspaul

composer.json

@@ -10,16 +10,16 @@
         }
     ],
     "require": {
-        "php": ">=5.6",
+        "php": ">=7.0",
         "illuminate/support": "^5.4",
         "illuminate/database": "^5.4",
-        "illuminate/validation": "^5.4",
-        "satooshi/php-coveralls": "^1.0"
+        "illuminate/validation": "^5.4"
     },
     "require-dev": {
         "phpunit/phpunit": "^6.0",
         "mockery/mockery": "^0.9.9",
-        "squizlabs/php_codesniffer": "^2.8"
+        "squizlabs/php_codesniffer": "^2.8",
+        "satooshi/php-coveralls": "^1.0"
     },
     "autoload": {
         "psr-4": {