AppVeyor: update to go 1.12.9

tao12345666333 · tao12345666333 · commit 7682acb9e7c9 · 2019-08-16T10:27:38.000+08:00
Signed-off-by: Jintao Zhang &lt;zhangjintao9020@gmail.com&gt;
diff --git a/.appveyor.yml b/.appveyor.yml
@@ -12,7 +12,7 @@ environment:
   GOPATH: C:\gopath
   CGO_ENABLED: 1
   matrix:
-    - GO_VERSION: 1.12.8
+    - GO_VERSION: 1.12.9
 
 before_build:
   - choco install -y mingw --version 5.3.0
