caption.sty v3.5a (2020/09/02) and babel-french

Via e-mail:

I noticed a glitch with the following test file:

\documentclass{acmart}
\usepackage[french,american]{babel}
\begin{document}
\begin{figure}[htp]
  \fbox{English}
  \caption{A caption}
\end{figure}

\selectlanguage{french}
\begin{figure}[htp]
  \fbox{French}
  \caption{Ma figure}
\end{figure}
\end{document}

acmart.cls loads caption.sty and sets labelsep=period which is fine for French too. The new caption.sty forces labelsep to be a colon (with a preceding space) in French :-(