fix(externalIpProvider/plain): when reading response body

pkg/externalIpProvider/plain/plain.go

@@ -2,6 +2,7 @@ package externalIpProvider
 
 import (
 	"errors"
+	"io"
 	"net"
 	"net/http"
 	"net/url"
@@ -40,12 +41,15 @@ func (p *ExternalIpProviderImplPlain) GetExternalIp() (net.IP, error) {
 	}
 
 	if res.StatusCode != 200 {
+		res.Body.Close()
 		return nil, errors.New("unexpected status code")
 	}
 
-	responseBody := make([]byte, res.ContentLength)
-	res.Body.Read(responseBody)
-	defer res.Body.Close()
+	responseBody, err := io.ReadAll(res.Body)
+	res.Body.Close()
+	if err != nil {
+		return nil, err
+	}
 
 	parsedIp := net.ParseIP(string(responseBody))
 	if parsedIp == nil {