Fix lint errors of io.Close() (#270)

* Check io.Close() errors

* Fix

Author: int128

e2e_test/client/client.go

@@ -30,7 +30,11 @@ func Get(url string) (int, string, error) {
 	if err != nil {
 		return 0, "", fmt.Errorf("could not send a request: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() {
+		if err := resp.Body.Close(); err != nil {
+			panic(err)
+		}
+	}()
 	b, err := io.ReadAll(resp.Body)
 	if err != nil {
 		return resp.StatusCode, "", fmt.Errorf("could not read response body: %w", err)

server.go

@@ -19,7 +19,10 @@ func receiveCodeViaLocalServer(ctx context.Context, cfg *Config) (string, error)
 	if err != nil {
 		return "", fmt.Errorf("could not start a local server: %w", err)
 	}
-	defer localServerListener.Close()
+	defer func() {
+		// The listener may be closed by the server. No need to check the error.
+		_ = localServerListener.Close()
+	}()
 
 	if cfg.OAuth2Config.RedirectURL == "" {
 		var localServerURL url.URL