Consider the following MWE

```
\documentclass{article}
\usepackage{caption}
\usepackage{subcaption}
\begin{document}
\begin{figure}
  \begin{subfigure}[t]{.5\linewidth}
    \centering
    \rule{3cm}{3cm}
    \caption{First subfigure}
  \end{subfigure}%
  \begin{subfigure}[t]{.5\linewidth}
    \centering
    \rule{3cm}{3cm}
    \caption{Second subfigure}
  \end{subfigure}
\caption{A figure}
\end{figure}
\end{document}

```

How do I reduce from the preamble (either as a package option or a setting) the separation between the caption of the subfigures and the caption of the figure?