Merge pull request #7 from Kdyby/license-names-fix

Fix license names deprecated in SPDX 3.0

composer.json

@@ -4,7 +4,7 @@
     "description": "Time provider, providing consistent current date, time, datetime and timezone across the request.",
     "keywords": ["kdyby", "date", "time", "datetime", "microseconds", "clock", "provider", "symfony", "bundle"],
     "homepage": "http://kdyby.org",
-    "license": ["BSD-3-Clause", "GPL-2.0", "GPL-3.0"],
+    "license": ["BSD-3-Clause", "GPL-2.0-only", "GPL-3.0-only"],
     "require": {
         "php": "^7.1",
         "kdyby/datetime-provider": "@dev",