Fix heatmap issues used in ssim baselines matlab code examples data distribution plots heatmap

[gilbertogalvis]

This PR fix heatmap issues tested in
https://github.com/plotly/ssim_baselines/tree/main/matlab/code-examples/data-distribution-plots/heatmap

[VolKa79]

Tested for all from
https://github.com/plotly/ssim_baselines/tree/main/matlab/code-examples/data-distribution-plots/heatmap
Looks good, of course except of ansence of that black separate lines

And with the last function, where:
tbl = readtable('TemperatureData.csv');
months = categorical(tbl.Month);
years = categorical(tbl.Year);
xlabels = categories(months);
ylabels = categories(years);
nummonths = numel(xlabels);
numyears = numel(ylabels);
x = double(months);
y = double(years);
temps = tbl.TemperatureF;
cdata = accumarray([y,x],temps,[numyears,nummonths],@max,NaN);
h = heatmap(xlabels,ylabels,cdata);

we have an issue with NaN values

[gilbertogalvis]

Tested for all from
https://github.com/plotly/ssim_baselines/tree/main/matlab/code-examples/data-distribution-plots/heatmap
Looks good, of course except of ansence of that black separate lines

And with the last function, where:
tbl = readtable('TemperatureData.csv');
months = categorical(tbl.Month);
years = categorical(tbl.Year);
xlabels = categories(months);
ylabels = categories(years);
nummonths = numel(xlabels);
numyears = numel(ylabels);
x = double(months);
y = double(years);
temps = tbl.TemperatureF;
cdata = accumarray([y,x],temps,[numyears,nummonths],@max,NaN);
h = heatmap(xlabels,ylabels,cdata);

we have an issue with NaN values

Excellent! Thanks a lot for test it @VolKa79. That's observations are good! I will hope it.

For now I will merge this with the master and in the future I will try to fix it. For now this works to upscale the SSIM for heatmap