Remove usage of go-ieproxy for windows (#10009)

There is a potential for deadlock on Windows 10
refer https://github.com/mattn/go-ieproxy/issues/17 

remove this dependency for now.

cmd/update.go

@@ -32,7 +32,6 @@ import (
 	"time"
 
 	"github.com/inconshreveable/go-update"
-	"github.com/mattn/go-ieproxy"
 	xhttp "github.com/minio/minio/cmd/http"
 	"github.com/minio/minio/cmd/logger"
 	"github.com/minio/minio/pkg/env"
@@ -409,7 +408,7 @@ const updateTimeout = 10 * time.Second
 
 func getUpdateTransport(timeout time.Duration) http.RoundTripper {
 	var updateTransport http.RoundTripper = &http.Transport{
-		Proxy:                 ieproxy.GetProxyFunc(),
+		Proxy:                 http.ProxyFromEnvironment,
 		DialContext:           xhttp.NewCustomDialContext(timeout),
 		IdleConnTimeout:       timeout,
 		TLSHandshakeTimeout:   timeout,

cmd/utils.go

@@ -39,7 +39,6 @@ import (
 	"sync"
 	"time"
 
-	"github.com/mattn/go-ieproxy"
 	xhttp "github.com/minio/minio/cmd/http"
 	"github.com/minio/minio/cmd/logger"
 	"github.com/minio/minio/pkg/handlers"
@@ -454,7 +453,7 @@ func newCustomHTTPTransport(tlsConfig *tls.Config, dialTimeout time.Duration) fu
 	// For more details about various values used here refer
 	// https://golang.org/pkg/net/http/#Transport documentation
 	tr := &http.Transport{
-		Proxy:                 ieproxy.GetProxyFunc(),
+		Proxy:                 http.ProxyFromEnvironment,
 		DialContext:           xhttp.NewCustomDialContext(dialTimeout),
 		MaxIdleConnsPerHost:   16,
 		MaxIdleConns:          16,