Update OC preview version.

Author: sarahelsaig

ShowOrchard.Theme/ShowOrchard.Theme.csproj

@@ -15,11 +15,11 @@
     </ItemGroup>
 
     <ItemGroup>
-        <PackageReference Include="OrchardCore.Theme.Targets" Version="2.0.0-preview-18259" />
-        <PackageReference Include="OrchardCore.ContentManagement" Version="2.0.0-preview-18259" />
-        <PackageReference Include="OrchardCore.DisplayManagement" Version="2.0.0-preview-18259" />
-        <PackageReference Include="OrchardCore.ResourceManagement" Version="2.0.0-preview-18259" />
-        <PackageReference Include="OrchardCore.Taxonomies" Version="2.0.0-preview-18259" />
+        <PackageReference Include="OrchardCore.Theme.Targets" Version="2.0.0-preview-18268" />
+        <PackageReference Include="OrchardCore.ContentManagement" Version="2.0.0-preview-18268" />
+        <PackageReference Include="OrchardCore.DisplayManagement" Version="2.0.0-preview-18268" />
+        <PackageReference Include="OrchardCore.ResourceManagement" Version="2.0.0-preview-18268" />
+        <PackageReference Include="OrchardCore.Taxonomies" Version="2.0.0-preview-18268" />
     </ItemGroup>
 
     <PropertyGroup>