Bring Go version current

Author: gliptak

circle.yml

@@ -1,7 +1,7 @@
 machine:
   pre:
-    - sudo curl -O https://storage.googleapis.com/golang/go1.7.5.linux-amd64.tar.gz
-    - sudo tar -xvf go1.7.5.linux-amd64.tar.gz
+    - sudo curl -O https://storage.googleapis.com/golang/go1.8.3.linux-amd64.tar.gz
+    - sudo tar -xvf go1.8.3.linux-amd64.tar.gz
     - sudo rm -fr /usr/local/go
     - sudo mv go /usr/local/go
   environment: