Move coveralls to require-dev

Author: Sevavietl

composer.json

@@ -3,12 +3,12 @@
     "description": "PHP type validator",
     "type": "library",
     "require": {
-        "php": ">=7.1",
-        "php-coveralls/php-coveralls": "^2.1"
+        "php": ">=7.1"
     },
     "require-dev": {
         "phpunit/phpunit": "^7.3",
-        "phpstan/phpstan": "^0.10.3"
+        "phpstan/phpstan": "^0.10.3",
+        "php-coveralls/php-coveralls": "^2.1"
     },
     "autoload": {
         "psr-4": {