Requiring drupal/core ^8.0. (#812)

Author: grasmash

template/composer.json

@@ -13,7 +13,7 @@
         "drupal/acquia_connector": "^1.5.0",
         "drupal/acsf": "^1.32.0",
         "drupal/cog": "^1.0.0",
-        "drupal/core": "*@stable",
+        "drupal/core": "^8.0",
         "drupal/features": "^3.0.0",
         "drupal/memcache": "^2.0.0-alpha2",
         "drupal/seckit": "^1.0.0-alpha2",