Upgrade to circleci2 (#14)

* Upgraded circleci to 2.0, upped mocha version

* Locking down dev dependencies

.circleci/config.yml

@@ -0,0 +1,14 @@
+version: 2
+jobs:
+  test:
+    docker:
+    - image: circleci/node:8.12.0-jessie
+    steps:
+    - checkout
+    - run: npm i
+    - run: npm test
+workflows:
+  version: 2
+  build_and_test:
+    jobs:
+    - test

package.json

@@ -1,6 +1,6 @@
 {
     "name": "wget-improved",
-    "version": "3.0.1",
+    "version": "3.0.2",
     "description": "wget in nodejs, forked from wuchengwei/node-wget to add improvements and help maintain the project",
     "keywords": [
         "download",
@@ -33,12 +33,12 @@
     },
     "license": "MIT",
     "devDependencies": {
-        "chai": "^4.0.2",
-        "express": "^4.16.3",
-        "mocha": "^5.2.0",
-        "request": "^2.88.0"
+        "chai": "4.0.2",
+        "express": "4.16.3",
+        "mocha": "5.2.0",
+        "request": "2.88.0"
     },
     "scripts": {
-        "test": "mocha test/test.js"
+        "test": "mocha test/test.js --exit"
     }
 }