Update node and npm dependencies (#343)

node: >=8.1.0
npm: >=5.1.0

README.md

@@ -9,7 +9,7 @@ Agent is the configuration application of the [Ultimate Hacking Keyboard](https:
 
 ## Set up instructions
 
-First up, make sure that node >=4.x.x and npm >=3.x.x are installed on your system. Next up:
+First up, make sure that node >=8.1.x and npm >=5.1.x are installed on your system. Next up:
 
 ```
 git clone git@github.com:UltimateHackingKeyboard/agent.git

appveyor.yml

@@ -4,7 +4,7 @@ environment:
   GH_TOKEN:
     secure: 3IebpEKmC39codi1wT6dXx8mql4/mCL1JzZ7lir7GQ5MWRnCxlED2OXbiKHHigDV
   matrix:
-    - nodejs_version: 6.9.4
+    - nodejs_version: "8"
 
 cache:
   - node_modules -> package.json

electron/src/package.json

@@ -10,8 +10,8 @@
   },
   "license": "GPL-3.0",
   "engines": {
-    "node": ">=6.9.5 <7.0.0",
-    "npm": ">=3.10.7 <4.0.0"
+    "node": ">=8.1.0 <9.0.0",
+    "npm": ">=5.1.0 <6.0.0"
   },
   "dependencies": {
     "node-hid": "0.5.4",

package.json

@@ -10,8 +10,8 @@
   },
   "license": "GPL-3.0",
   "engines": {
-    "node": ">=6.9.5 <7.0.0",
-    "npm": ">=3.10.7 <4.0.0"
+    "node": ">=8.1.0 <9.0.0",
+    "npm": ">=5.1.0 <6.0.0"
   },
   "devDependencies": {
     "@ngrx/store-devtools": "3.2.4",