update node versions to current stable release

Author: locks

.travis.yml

@@ -54,7 +54,7 @@ matrix:
         - cargo test
     - name: Frontend
       language: node_js
-      node_js: 10
+      node_js: 12
       install:
         - npm ci
       before_script: skip

docs/CONTRIBUTING.md

@@ -86,8 +86,8 @@ as well.
 
 In order to run the frontend on Windows and macOS, you will need to have installed:
 
-- [node](https://nodejs.org/en/) >= 6.10.0 (see .travis.yml for what we currently use)
-- [npm](https://www.npmjs.com/get-npm) >= 4.0.0
+- [node](https://nodejs.org/en/) >= 12.9.1 (see `package.json` and `.travis.yml` for what we currently use)
+- [npm](https://www.npmjs.com/get-npm) >= 6.10.2
 
 Follow the links for each of these tools for their recommended installation
 instructions. If you already have these tools, or you have a different

frontend.Dockerfile

@@ -1,4 +1,4 @@
-FROM node:8.6-alpine
+FROM node:12.9-alpine
 
 WORKDIR /app
 COPY package.json package-lock.json /app/

package.json

@@ -83,8 +83,8 @@
     "timekeeper": "^2.1.0"
   },
   "engines": {
-    "node": "^8.1.3",
-    "npm": "^5.1.0"
+    "node": "^12.9.1",
+    "npm": "^6.10.2"
   },
   "private": true,
   "prettier": {