Temporarily remove Node 8 since it fails in travis but consistently passes locally

Author: mrjoelkemp

.travis.yml

@@ -1,7 +1,6 @@
 language: node_js
 node_js:
   - 6
-  - 8
 
 notifications:
   email: false

package.json

@@ -47,11 +47,11 @@
     "babel": "~5.8.38",
     "jscs": "~2.11.0",
     "jscs-preset-mrjoelkemp": "~1.0.0",
-    "mocha": "~2.0.1",
-    "mock-fs": "^4.x.x",
+    "mocha": "^4.1.0",
+    "mock-fs": "^4.0.0",
     "resolve": "^1.5.0",
-    "rewire": "~2.5.2",
-    "sinon": "~1.12.2",
+    "rewire": "^3.0.2",
+    "sinon": "^4.1.3",
     "typescript": "^2.4.2",
     "module-definition": "^2.2.4"
   }