Numbering figures in LaTeX with decimal points

Question

I want to number a set of {figures} in LaTeX as follows:

\section{introduction}

\begin{figure}[H]

    \centering

    \includegraphics[width=0.5\textheight]{nameof the figure}

    \caption{specification for the figure}

    \label{refertofigure1}

\end{figure}

This code renders as Figure 1: specification for the figure, and I want it display:

• The initial figure: Figure 1.1: specification for the figure
• If I add another figure: Figure 1.2: specification for the figure
• If I add another section: Figure 2.1: specification for the figure

How can I express this in LaTeX?