Add Go 1.13 to the tested version in the travis build file (#350)

ccojocar · gcmurphy · commit e442cf30a8aa · 2019-09-09T21:10:58.000+10:00
Signed-off-by: Cosmin Cojocar &lt;cosmin.cojocar@gmx.ch&gt;
diff --git a/.travis.yml b/.travis.yml
@@ -3,6 +3,7 @@ language: go
 go:
   - "1.11.x"
   - "1.12.x"
+  - "1.13.x"
   - tip
 
 install:
