Check make serve

For check logs in ci. This should be removed later.
Seems installation would not be done in successfully.

Author: shu-mutou

.github/workflows/ci.yml

@@ -106,7 +106,7 @@ jobs:
       - run: |
           export GOPATH=$(go env GOPATH)
           export PATH=$PATH:$GOPATH/bin
-          make serve &
+          make serve
       - run: |
           export GOPATH=$(go env GOPATH)
           export PATH=$PATH:$GOPATH/bin