Update CI config files to use Node-12.x (#3919)

* ci(.travis.yml): Update Travis config to use Node-12

Downgrade to Node-10 for browser tests so we can use the pre-built canvas package.

* ci(appveyor.yml): Update AppVeyor config to use Node-12

Future-proof install for Node versions to use alternative Node update method if pre-installed version unavailable.

.travis.yml

@@ -11,10 +11,11 @@ stages:
 
 # defaults
 language: node_js
-node_js: '11'
+node_js: '12'
 addons:
   apt:
     packages:
+      # Growl
       - libnotify-bin
 # `nvm install` happens before the cache is restored, which means
 # we must install our own npm elsewhere (`~/npm`)
@@ -49,6 +50,8 @@ jobs:
       node_js: '6'
 
     - script: npm start test.bundle test.browser
+      # XXX: update when canvas supplies a prebuilt binary for Node.js v12.x
+      node_js: 10
       install: npm ci # we need the native modules here
       addons:
         artifacts:

appveyor.yml

@@ -12,7 +12,7 @@ shallow_clone: true
 clone_depth: 1
 environment:
   matrix:
-    - nodejs_version: '11'
+    - nodejs_version: '12'
     - nodejs_version: '10'
     - nodejs_version: '8'
     - nodejs_version: '6'
@@ -35,7 +35,14 @@ install:
   ## Node-related installs
   - ps: Add-AppveyorMessage "Installing Node..."
   - set PATH=%APPDATA%\npm;C:\MinGW\bin;%PATH%
-  - ps: Install-Product node $env:nodejs_version x64
+  ## Prefer pre-installed Node versions, with fallback to manual update
+  - ps: |
+      try {
+      Install-Product node $env:nodejs_version $env:platform
+      } catch {
+      Add-AppveyorMessage "  install failed - attempting manual update..."
+      Update-NodeJsInstallation (Get-NodeJsLatestBuild $env:nodejs_version) $env:platform
+      }
   - ps: Add-AppveyorMessage "Installing npm..."
   - npm install -g npm
   ## Mocha-related package installs