Update (c) year to 2020

build/SharedVersion.props

@@ -3,7 +3,7 @@
   <PropertyGroup>
     <Product>Avalonia</Product>
     <Version>0.9.999</Version>
-    <Copyright>Copyright 2019 &#169; The AvaloniaUI Project</Copyright>
+    <Copyright>Copyright 2020 &#169; The AvaloniaUI Project</Copyright>
     <PackageProjectUrl>https://avaloniaui.net</PackageProjectUrl>
     <RepositoryUrl>https://github.com/AvaloniaUI/Avalonia/</RepositoryUrl>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>

src/Avalonia.Dialogs/AboutAvaloniaDialog.xaml

@@ -99,7 +99,7 @@
       </StackPanel>
      </StackPanel> 
     <StackPanel VerticalAlignment="Bottom" Margin="10">
-      <TextBlock Text="© 2019 The Avalonia Project" TextWrapping="Wrap" HorizontalAlignment="Center" />
+      <TextBlock Text="© 2020 The Avalonia Project" TextWrapping="Wrap" HorizontalAlignment="Center" />
     </StackPanel>
   </Grid>
 </Window>