[CI] Run with go 1.12

Author: achilleas-k

.travis.yml

@@ -12,11 +12,11 @@ env:
 
 matrix:
   include:
-    - go: "1.11.x"
+    - go: "1.12.x"
       os: linux
     - go: tip
       os: linux
-    - go: "1.11.x"
+    - go: "1.12.x"
       os: osx
       addons:
         homebrew:

appveyor.yml

@@ -3,7 +3,7 @@ build: off
 
 clone_folder: C:\gopath\src\github.com\G-Node\gin-cli
 
-stack: go 1.11
+stack: go 1.12
 
 environment:
   SRCDIR: C:\gopath\src\github.com\G-Node\gin-cli