Package appveyor artifacts after test

Artifacts apparently get listed before the before_deploy step.
Not having them ready at that point results in an error message:

  No artifacts found matching
  'build\stage\gagern\node-libtidy\releases\download\**\*.tar.gz' path
  No artifacts were published.
  Make sure you have specified correct artifacts filter.

Author: gagern

appveyor.yml

@@ -26,13 +26,13 @@ build_script:
 test_script:
   - npm test
 
+after_test:
+  - node_modules/.bin/node-pre-gyp package
+
 artifacts:
   - path: build\stage\gagern\node-libtidy\releases\download\**\*.tar.gz
     name: binary
 
-before_deploy:
-  - node_modules/.bin/node-pre-gyp package
-
 deploy:
   - provider: GitHub
     release: $(APPVEYOR_REPO_TAG_NAME)