chore: optimize package export excluding unuseful files

.gitattributes

@@ -0,0 +1,10 @@
+/CODE_OF_CONDUCT.md  export-ignore
+/Dockerfile          export-ignore
+/README.md           export-ignore
+/docker-compose.yml  export-ignore
+/phpunit.xml         export-ignore
+/tests               export-ignore
+/CONTRIBUTING.md     export-ignore
+/LICENSE             export-ignore
+/phpstan.neon        export-ignore
+/.travis.yml         export-ignore

.gitignore

@@ -1,2 +1,3 @@
 /vendor/
 .php_cs.cache
+.phpunit.result.cache

LICENSE

@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2017 Moon
+Copyright (c) 2018 Moon
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

composer.json

@@ -12,12 +12,12 @@
   },
   "require-dev": {
     "roave/security-advisories": "dev-master",
-    "phpunit/phpunit": "^6.2",
     "friendsofphp/php-cs-fixer": "^2.12",
     "damianopetrungaro/php-commitizen": "^0.1.2",
     "phpstan/phpstan": "^0.10.1",
     "php-coveralls/php-coveralls": "^2.1",
-    "jangregor/phpstan-prophecy": "^0.2.0"
+    "jangregor/phpstan-prophecy": "^0.2.0",
+    "phpunit/phpunit": "^7.3"
   },
   "authors": [
     {