Bump v6.0.0-nightly.20190206

package-lock.json

@@ -4449,7 +4449,8 @@
           "version": "2.1.1",
           "resolved": false,
           "integrity": "sha1-w7M6te42DYbg5ijwRorn7yfWVN8=",
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "aproba": {
           "version": "1.2.0",
@@ -4914,7 +4915,8 @@
           "version": "5.1.1",
           "resolved": false,
           "integrity": "sha512-kKvNJn6Mm93gAczWVJg7wH+wGYWNrDHdWvpUmHyEsgCtIwwo3bqPtV4tR5tuPaUhTOo/kvhVwd8XwwOllGYkbg==",
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "safer-buffer": {
           "version": "2.1.2",
@@ -4978,6 +4980,7 @@
           "resolved": false,
           "integrity": "sha1-ajhfuIU9lS1f8F0Oiq+UJ43GPc8=",
           "dev": true,
+          "optional": true,
           "requires": {
             "ansi-regex": "^2.0.0"
           }
@@ -5026,13 +5029,15 @@
           "version": "1.0.2",
           "resolved": false,
           "integrity": "sha1-tSQ9jz7BqjXxNkYFvA0QNuMKtp8=",
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "yallist": {
           "version": "3.0.2",
           "resolved": false,
           "integrity": "sha1-hFK0u36Dx8GI2AQcGoN8dz1ti7k=",
-          "dev": true
+          "dev": true,
+          "optional": true
         }
       }
     },