Merge branch 'ci/go-1.13'

.travis.yml

@@ -12,9 +12,9 @@ env:
 
 # disable travis install
 install:
-  # Manually download and install Go 1.12 instead of using gimme.
+  # Manually download and install Go 1.13 instead of using gimme.
   # It looks like gimme Go causes some errors on go-test for Wasm.
-  - wget -O go.tar.gz https://dl.google.com/go/go1.12.10.linux-amd64.tar.gz
+  - wget -O go.tar.gz https://dl.google.com/go/go1.13.4.linux-amd64.tar.gz
   - tar -C ~ -xzf go.tar.gz
   - rm go.tar.gz
   - export GOROOT=~/go