`gcloud app deploy`命令选择了错误的GOPATH

I am Using go1.11.4 for postgre connection and strictly using GAE standard. My app.yaml is as below-

runtime: go111

service: alerting-postgre-service-ad

In my main.go my imports are as below-

package main
 import (
    "database/sql"
    "encoding/json"
    "fmt"
    "log"
    "net/http"
//"google.golang.org/appengine"
_ "github.com/GoogleCloudPlatform/cloudsqlproxy/proxy/dialers/postgres"
)

when I execute command - gcloud app deploy app.yaml on console I get follwoing error-

ERROR: (gcloud.app.deploy) Error Response: [9] Cloud build a3389d5a-7969-4211-9c96-2377f487b604 status: FAILURE. Build error details: srv/main.go:10:2: cannot find package "github.com/GoogleCloudPlatform/cloudsql-proxy/proxy/dialers/postgres" in any of: /usr/local/go/src/github.com/GoogleCloudPlatform/cloudsql-proxy/proxy/dialers/postgres (from $GOROOT) /tmp/staging321436436/srv/gopath/src/github.com/GoogleCloudPlatform/cloudsql-proxy/proxy/dialers/postgres (from $GOPATH)

As I am using windows 10, I don't know where to fix my gopath as my gopath is already set to C:\Users\aniruddh.dwivedi\go while goroot is C:\Go