grpc/interceptor: check success status code when fetching github token

Author: tronghn

pkg/grpc/interceptor/auth/client.go

@@ -112,6 +112,10 @@ func (g *GitHubTokenInterceptor) Token(ctx context.Context) (string, error) {
 	}
 	defer resp.Body.Close()
 
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		return "", fmt.Errorf("unexpected status code: %s", resp.Status)
+	}
+
 	body, err := io.ReadAll(resp.Body)
 	if err != nil {
 		return "", fmt.Errorf("reading body: %w", err)