switch to ubuntu builds

appveyor.yml

@@ -1,30 +1,16 @@
 image:
-- Visual Studio 2017
+- Ubuntu1804
 
 branches:
   except:
     - gh-pages
 
-init:
-- ps: |
-    if($isWindows -and $env:DEBUG_RDP -eq "true") {
-      iex ((new-object net.webclient).DownloadString(`
-        'https://raw.githubusercontent.com/appveyor/ci/master/scripts/enable-rdp.ps1'))
-    }
-- ps: Install-Product node 10
+stack: node 10
 
 before_build:
-- cmd: node --version
-- cmd: npm --version
+- node --version
+- npm --version
 
 build_script:
-- cmd: npm install
-- cmd: npm run deploy:ci
-
-on_finish:
-  - ps: |
-      if($isWindows -and $env:DEBUG_RDP -eq "true") {
-        $blockRdp = $true
-        iex ((new-object net.webclient).DownloadString(`
-          'https://raw.githubusercontent.com/appveyor/ci/master/scripts/enable-rdp.ps1'))
-      }
+- npm install
+- npm run deploy:ci