Update dependencies

Closes #17.

Author: TooTallNate

package.json

@@ -27,17 +27,17 @@
   "homepage": "https://github.com/TooTallNate/node-proxy-agent",
   "dependencies": {
     "agent-base": "^4.2.0",
-    "debug": "^2.6.8",
-    "http-proxy-agent": "^1.0.0",
-    "https-proxy-agent": "^1.0.0",
-    "lru-cache": "^2.6.5",
-    "pac-proxy-agent": "^2.0.0",
+    "debug": "^3.1.0",
+    "http-proxy-agent": "^2.1.0",
+    "https-proxy-agent": "^2.2.1",
+    "lru-cache": "^4.1.2",
+    "pac-proxy-agent": "^2.0.1",
     "proxy-from-env": "^1.0.0",
-    "socks-proxy-agent": "^3.0.0"
+    "socks-proxy-agent": "^4.0.0"
   },
   "devDependencies": {
-    "mocha": "^3.4.2",
-    "proxy": "0.2.3",
+    "mocha": "^5.0.5",
+    "proxy": "0.2.4",
     "socksv5": "0.0.6",
     "stream-to-buffer": "0.1.0"
   }