s0artcl: slightly decrease afterskip for subsubsections

s0artcl.dtx

@@ -93,6 +93,7 @@
 % \subsection{Optimize Vertical Spacing}
 %    \begin{macrocode}
 \RedeclareSectionCommand[afterskip=0.5em]{section}
+\RedeclareSectionCommand[afterskip=0.1em]{subsubsection}
 \RedeclareSectionCommand[beforeskip=.5\parskip, afterskip=-1em]{paragraph}
 \setlength{\parindent}{0em}
 \RequirePackage{enumitem}