travis: upgrade Go version to 1.10.1

Signed-off-by: Gyuho Lee <gyuhox@gmail.com>

.travis.yml

@@ -6,7 +6,7 @@ sudo: required
 services: docker
 
 go:
-- "1.10"
+- 1.10.1
 - tip
 
 notifications:
@@ -30,7 +30,7 @@ matrix:
   - go: tip
     env: TARGET=amd64-go-tip
   exclude:
-  - go: "1.10"
+  - go: 1.10.1
     env: TARGET=amd64-go-tip
   - go: tip
     env: TARGET=amd64