[maintenance] Update dependencies

Notes:

  The following dependencies have not been updated,
  as they break our tests:

  * eslint
  * eslint-config-airbnb

package.json

@@ -29,8 +29,8 @@
     "bluebird": "^3.3.4",
     "debug": "^2.2.0",
     "depd": "^1.1.0",
-    "eventemitter3": "^1.2.0",
-    "file-type": "^3.8.0",
+    "eventemitter3": "^2.0.2",
+    "file-type": "^4.0.0",
     "mime": "^1.3.4",
     "pump": "^1.0.1",
     "request": "^2.69.0",
@@ -38,7 +38,7 @@
   },
   "devDependencies": {
     "babel-cli": "^6.6.5",
-    "babel-eslint": "^6.0.4",
+    "babel-eslint": "^7.1.1",
     "babel-plugin-transform-class-properties": "^6.6.0",
     "babel-plugin-transform-es2015-destructuring": "^6.6.5",
     "babel-plugin-transform-es2015-parameters": "^6.7.0",
@@ -49,13 +49,13 @@
     "babel-preset-es2015": "^6.6.0",
     "babel-register": "^6.7.2",
     "contributor": "^0.1.25",
-    "eslint": "^2.11.1",
-    "eslint-config-airbnb": "^6.1.0",
-    "eslint-plugin-mocha": "^2.0.0",
+    "eslint": "^2.13.1",
+    "eslint-config-airbnb": "^6.2.0",
+    "eslint-plugin-mocha": "^4.8.0",
     "is": "^3.1.0",
     "istanbul": "^1.1.0-alpha.1",
-    "jsdoc-to-markdown": "^1.3.3",
-    "mocha": "^2.4.5",
+    "jsdoc-to-markdown": "^2.0.1",
+    "mocha": "^3.2.0",
     "mocha-lcov-reporter": "^1.2.0",
     "node-static": "^0.7.9"
   },