Update composer.json to require latest stable version of Drupal (drupal-composer#424)

Author: grasmash

.travis.yml

@@ -37,7 +37,7 @@ install:
 
 script:
   - if [[ $RELEASE = dev ]]; then composer --verbose remove --no-update drupal/console; fi;
-  - if [[ $RELEASE = dev ]]; then composer --verbose require --no-update drupal/core:8.6.x-dev webflo/drupal-core-require-dev:8.6.x-dev; fi;
+  - if [[ $RELEASE = dev ]]; then composer --verbose require --no-update drupal/core:8.7.x-dev webflo/drupal-core-require-dev:8.7.x-dev; fi;
   - if [[ $RELEASE = dev ]]; then composer --verbose update; fi;
   - cd $TRAVIS_BUILD_DIR/web
   - ./../vendor/bin/drush site-install --verbose --yes --db-url=sqlite://tmp/site.sqlite

composer.json

@@ -20,14 +20,14 @@
         "cweagans/composer-patches": "^1.6.5",
         "drupal-composer/drupal-scaffold": "^2.5",
         "drupal/console": "^1.0.2",
-        "drupal/core": "~8.5.3",
+        "drupal/core": "^8.6.0",
         "drush/drush": "^9.0.0",
         "vlucas/phpdotenv": "^2.4",
         "webflo/drupal-finder": "^1.0.0",
         "webmozart/path-util": "^2.3"
     },
     "require-dev": {
-        "webflo/drupal-core-require-dev": "~8.5.3"
+        "webflo/drupal-core-require-dev": "^8.6.0"
     },
     "conflict": {
         "drupal/drupal": "*"