Need to update SecondaryAccentBrush to SecondaryHueMidBrush

[RichardRobertson]

Some resource keys changed in MaterialDesignInXAML and this is one I encountered that needs to be updated in the Dragablz Material theme. As a workaround in my current code, I'm just binding to the new resource key in a style.

Dragablz/Dragablz/Themes/MaterialDesign.xaml

Line 152 in da7a4e5

<Setter Property="local:MaterialDesignAssist.IndicatorBrush" Value="{DynamicResource SecondaryAccentBrush}" />

Dragablz/Dragablz/Themes/MaterialDesign.xaml

Line 270 in da7a4e5

<Border x:Name="SelectionHighlightBorder" Background="{DynamicResource SecondaryAccentBrush}" Width="2"