Updated OnTopic Library to the special preview of 5.2.0 (#260)

Updated OnTopic Library to the #260 build of the `revert-AttributeValueDictionary` branch. This reverts `AttributeValueDictionary` back to `AttributeDictionary`, in preparation to undo OnTopicCMS/OnTopic-Library#107). The conflict that was trying to avoid wasn't necessary.

Author: JeremyCaney

OnTopic.Editor.AspNetCore.Attributes/OnTopic.Editor.AspNetCore.Attributes.csproj

@@ -25,7 +25,7 @@
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
-    <PackageReference Include="OnTopic" Version="5.2.0-alpha.255" />
+    <PackageReference Include="OnTopic" Version="5.2.0-revert-AttributeValueDictionary.260" />
   </ItemGroup>
 
   <ItemGroup>

OnTopic.Editor.AspNetCore/OnTopic.Editor.AspNetCore.csproj

@@ -24,7 +24,7 @@
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
-    <PackageReference Include="OnTopic" Version="5.2.0-alpha.255" />
+    <PackageReference Include="OnTopic" Version="5.2.0-revert-AttributeValueDictionary.260" />
     <PackageReference Include="OnTopic.Data.Transfer" Version="2.0.0" />
     <PackageReference Include="OnTopic.AspNetCore.Mvc" Version="5.2.0-alpha.234" />
   </ItemGroup>