Wrapfigure with DecoRule Error

I would like to use a decoRule between the caption and note of a wrapfigure. I tried textwidth and some other things which did not work.
On the other hand, hrule works but produces errors which I believe are causing my .tex to crash currently.

Help would be much appreciated!! 🙂

documentclass{article}
usepackage[utf8]{inputenc}
usepackage{pgfplots}
usepackage{pgfplotstable}
pgfplotsset{compat=1.7}
usepackage{tikz}
usepackage{graphicx}
usepackage{subcaption}
usepackage{wrapfig}
usepackage{lipsum}


title{Example}
author{Name }
date{April 2021}

begin{document}

maketitle

section{Introduction}



begin{wrapfigure}{l}{0.5textwidth}
centering  
begin{tikzpicture}
begin{axis}[
    axis equal image, 
    scatter, 
    width=textwidth,
    height=6cm,
    colormap/viridis, 
    colorbar, 
        xticklabels={$alpha$-IgG, $beta$-IgG, $gamma$-IgG},xtick={0,1,2},
        yticklabels={$alpha$-IgG, $beta$-IgG, $gamma$-IgG},ytick={0,1,2},
    point meta min=0,
    point meta max=1,
    grid=minor, 
    minor tick num=1.0, 
    tickwidth=0pt, 
    y dir=reverse, 
    xticklabel pos=right, 
    enlargelimits={abs=0.5}, 
    scatter/@pre marker code/.append code={pgfplotstransformcoordinatex{sqrt(abs(pgfplotspointmeta))}
      scope[mark size=pgfplotsunitxlength*pgfmathresult/2, fill=mapped color]
    },
    scatter/@post marker code/.append code={
      endscope
    }
]
addplot+[
    point meta=explicit,
    only marks,
    ] table [
    x expr={int(mod(coordindex+0.01,3))},
    y expr={int((coordindex+0.01)/3))},
    meta=value
]{
X       Y   value

0.7     0   1.00
1.5     0   0.93
3.8     0   0.67

0.7     1   0.93
1.5     1   1.00
3.8     1   0.66

0.7     2   0.67
1.5     2   0.66
3.8     2   1.00
};
end{axis}
end{tikzpicture}
caption[Caption.]{Caption.
vspace{5pt}
hrule
vspace{5pt}
footnotesize{textit{Note.}}}
    label{fig:IgG}
end{wrapfigure}
lipsum[1-5]


end{document}