chore(deps): bump Microsoft.AspNetCore.App

Bumps [Microsoft.AspNetCore.App](https://github.com/aspnet/Universe) from 2.1.0 to 2.1.4.
- [Release notes](https://github.com/aspnet/Universe/releases)
- [Changelog](https://github.com/aspnet/Universe/blob/master/docs/CrossRepoBreakingChanges.md)
- [Commits](aspnet/Universe@2.1.0...2.1.4)

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

signalr-hubs/signalr-for-aspnet-core/signalr-for-aspnet-core.csproj

@@ -5,7 +5,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.AspNetCore.App" Version="2.1.0" />
+    <PackageReference Include="Microsoft.AspNetCore.App" Version="2.1.4" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="2.1.0" />
   </ItemGroup>