Why does this \adjustwidth not make the figure wider?

I’m trying to stretch a figure beyond \textwidth and I’m using \adjustwidth for it. For some reason it has no effect and I can’t quite figure out why that is the case. Here is the code:

\documentclass{article}
\usepackage[left=2.5cm,right=2.5cm,top=2.5cm,bottom=2cm,includefoot]{geometry}
\usepackage[demo]{graphicx}
\usepackage[english]{babel}
\usepackage{tikz}
\usepackage[utf8]{inputenc}
\usepackage{blindtext}
\usepackage{titlesec}
\usepackage{chngpage}           % Temporarily adjust side margins
\begin{document}

\begin{adjustwidth}{-1cm}{-1cm}
\begin{figure}
\centering
\renewcommand{\arraystretch}{3}
\begin{tabular*}{\textwidth}{@{}ccc@{}}
  \includegraphics[width=0.31\linewidth,height=2cm]{dummy} &
        \includegraphics[width=0.31\linewidth,height=2cm]{dummy}&
        \includegraphics[width=0.31\linewidth,height=2cm]{dummy}\\
    \includegraphics[width=0.31\linewidth,height=2cm]{dummy} &
        \includegraphics[width=0.31\linewidth,height=2cm]{dummy}&
        \includegraphics[width=0.31\linewidth,height=2cm]{dummy}
\end{tabular*}
\caption{\blindtext}
\end{figure}
\end{adjustwidth}

\blindtext

\end{document}