chore(package): update dependencies

https://greenkeeper.io/

package.json

@@ -37,17 +37,17 @@
   "license": "MIT",
   "homepage": "https://github.com/IndigoUnited/node-level-atomics",
   "devDependencies": {
-    "codacy-coverage": "^1.1.2",
+    "codacy-coverage": "^2.0.0",
     "coveralls": "^2.11.2",
     "expect.js": "^0.3.1",
-    "istanbul": "^0.3.17",
+    "istanbul": "^0.4.5",
     "leveldown": "^1.3.0",
     "levelup": "^1.2.1",
-    "mocha": "^2.2.5",
-    "mocha-lcov-reporter": "0.0.2"
+    "mocha": "^3.2.0",
+    "mocha-lcov-reporter": "1.2.0"
   },
   "dependencies": {
-    "async": "^1.3.0",
+    "async": "^2.1.4",
     "lock": "^0.1.2"
   }
 }