Should be tag name.

octalmage · octalmage · commit eb1c88929ef3 · 2018-03-03T15:26:03.000-06:00
diff --git a/appveyor.yml b/appveyor.yml
@@ -32,7 +32,7 @@ test_script:
   - npm test
 
 on_success:
-  - IF defined APPVEYOR_REPO_TAG npm run prebuild -- -u %GITHUB_TOKEN%
+  - IF defined APPVEYOR_REPO_TAG_NAME npm run prebuild -- -u %GITHUB_TOKEN%
 
 build: off
 version: "{build}"
