change GH_REF to SSH.

Zhili Yang · Zhili Yang · commit b00672794ce2 · 2017-10-06T15:39:41.000+08:00
diff --git a/.travis.yml b/.travis.yml
@@ -26,4 +26,4 @@ branches:
     - develop
 env:
  global:
-   - GH_REF: https://github.com/SysTick/systick.github.io.git
+   - GH_REF: git@github.com:SysTick/systick.github.io.git
