try to set GO11MODULES

Signed-off-by: Satoshi Moris Tagomori <tagomoris@gmail.com>

Author: tagomoris

.github/workflows/ci.yaml

@@ -23,6 +23,8 @@ jobs:
  - uses: actions/setup-go@v2
  with:
  go-version: ${{ matrix.golang }}
+ - name: Change GO11MODULES
+ run: go env -w GO111MODULE=auto
  - name: Install requirements
  run: |
  go get github.com/bmizerany/assert