build: replace AppVeyor with CircleCI Windows support (#343)

* docs: note that top-level await doesn't work with Node 12

.circleci/config.yml

@@ -73,7 +73,9 @@ steps-mac: &steps-mac
     - *step-save-cache
     - run: yarn test
 
-version: 2
+version: 2.1
+orbs:
+  win: circleci/[email protected]
 jobs:
   test-linux:
     docker:
@@ -83,6 +85,11 @@ jobs:
     macos:
       xcode: "11.1.0"
     <<: *steps-mac
+  test-windows:
+    executor:
+      name: win/vs2019
+      shell: bash.exe
+    <<: *steps-linux-win
 
   release:
     docker:
@@ -99,10 +106,12 @@ workflows:
     jobs:
       - test-linux
       - test-mac
+      - test-windows
       - release:
           requires:
             - test-linux
             - test-mac
+            - test-windows
           filters:
             branches:
               only:

README.md

@@ -24,6 +24,8 @@ const electronInstaller = require('electron-winstaller');
 Then do a build like so..
 
 ```javascript
+// NB: Use this syntax within an async function, Node does not have support for
+//     top-level await as of Node 12.
 try {
   await electronInstaller.createWindowsInstaller({
     appDirectory: '/tmp/build/my-app-64',