removing deprecated PackageTargetFallback

Author: wwwlicious

src/IdentityServer4.Contrib.ServiceStack/IdentityServer4.Contrib.ServiceStack.csproj

@@ -13,7 +13,6 @@
     <PackageReleaseNotes>https://github.com/wwwlicious/servicestack-authentication-identityserver/releases</PackageReleaseNotes>
     <PackageIconUrl>https://identityserver.github.io/Documentation/assets/images/icons/IDserver_icon128.jpg</PackageIconUrl>
     <PackageProjectUrl>https://github.com/wwwlicious/servicestack-authentication-identityserver</PackageProjectUrl>
-    <PackageTargetFallback>$(PackageTargetFallback);dotnet5.6;portable-net45+win8</PackageTargetFallback>
   </PropertyGroup>
 
   <ItemGroup>

src/samples/IdentityServer4.SelfHost/IdentityServer4.SelfHost.csproj

@@ -6,7 +6,6 @@
     <AssemblyName>IdentityServer4.SelfHost</AssemblyName>
     <OutputType>Exe</OutputType>
     <PackageId>IdentityServer4.SelfHost</PackageId>
-    <PackageTargetFallback>$(PackageTargetFallback);dotnet5.6;portable-net45+win8</PackageTargetFallback>
   </PropertyGroup>
 
   <ItemGroup>

src/samples/UserAuthProvider.ServiceStack.Core.SelfHost/UserAuthProvider.ServiceStack.Core.SelfHost.csproj

@@ -6,7 +6,6 @@
     <AssemblyName>UserAuthProvider.ServiceStack.Core.SelfHost</AssemblyName>
     <OutputType>Exe</OutputType>
     <PackageId>UserAuthProvider.ServiceStack.Core.SelfHost</PackageId>
-    <PackageTargetFallback>$(PackageTargetFallback);dotnet5.6;portable-net45+win8</PackageTargetFallback>
   </PropertyGroup>
 
   <ItemGroup>