Remove [RequiresPreviewFeatures] from System.Security.Cryptography.Cose

src/libraries/System.Security.Cryptography.Cose/ref/System.Security.Cryptography.Cose.csproj

 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <TargetFrameworks>$(NetCoreAppCurrent);$(NetCoreAppMinimum);netstandard2.0;$(NetFrameworkMinimum)</TargetFrameworks>
-    <EnablePreviewFeatures>True</EnablePreviewFeatures>
-    <GenerateRequiresPreviewFeaturesAttribute>true</GenerateRequiresPreviewFeaturesAttribute>
   </PropertyGroup>
 
   <ItemGroup>
     <Compile Include="System.Security.Cryptography.Cose.cs" />
   </ItemGroup>
 
-  <ItemGroup Condition="'$(TargetFrameworkIdentifier)' != '.NETCoreApp'">
-    <Compile Include="$(CoreLibSharedDir)System\Runtime\Versioning\RequiresPreviewFeaturesAttribute.cs"
-             Link="System\Runtime\Versioning\RequiresPreviewFeaturesAttribute.cs" />
-  </ItemGroup>
-
   <ItemGroup Condition="'$(TargetFrameworkIdentifier)' != '.NETCoreApp'">
     <PackageReference Include="System.Memory" Version="$(SystemMemoryVersion)" />
   </ItemGroup>

src/libraries/System.Security.Cryptography.Cose/src/System.Security.Cryptography.Cose.csproj

@@ -2,8 +2,6 @@
   <PropertyGroup>
     <TargetFrameworks>$(NetCoreAppCurrent);$(NetCoreAppMinimum);netstandard2.0;$(NetFrameworkMinimum)</TargetFrameworks>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
-    <EnablePreviewFeatures>True</EnablePreviewFeatures>
-    <GenerateRequiresPreviewFeaturesAttribute>true</GenerateRequiresPreviewFeaturesAttribute>
     <IsPackable>true</IsPackable>
     <!-- Disabling baseline validation since this is a brand new package.
        Once this package has shipped a stable version, the following line
@@ -31,10 +29,6 @@
     <Compile Include="System\Security\Cryptography\Cose\SigStructureContext.cs" />
   </ItemGroup>
 
-  <ItemGroup Condition="'$(TargetFrameworkIdentifier)' != '.NETCoreApp'">
-    <Compile Include="$(CoreLibSharedDir)System\Runtime\Versioning\RequiresPreviewFeaturesAttribute.cs" Link="System\Runtime\Versioning\RequiresPreviewFeaturesAttribute.cs" />
-  </ItemGroup>
-
   <ItemGroup>
     <ProjectReference Include="$(LibrariesProjectRoot)System.Formats.Cbor\src\System.Formats.Cbor.csproj" />
   </ItemGroup>

src/libraries/System.Security.Cryptography.Cose/tests/System.Security.Cryptography.Cose.Tests.csproj

@@ -2,8 +2,6 @@
   <PropertyGroup>
     <TargetFrameworks>$(NetCoreAppCurrent);net48</TargetFrameworks>
     <Nullable>enable</Nullable>
-    <EnablePreviewFeatures>true</EnablePreviewFeatures>
-    <GenerateRequiresPreviewFeaturesAttribute>true</GenerateRequiresPreviewFeaturesAttribute>
     <IgnoreForCI Condition="'$(TargetOS)' == 'Browser'">true</IgnoreForCI>
   </PropertyGroup>
 
@@ -34,10 +32,6 @@
     <Compile Include="CoseTestHelpers.cs" />
   </ItemGroup>
   
-  <ItemGroup Condition="'$(TargetFrameworkIdentifier)' != '.NETCoreApp'">
-    <Compile Include="$(CoreLibSharedDir)System\Runtime\Versioning\RequiresPreviewFeaturesAttribute.cs" Link="System\Runtime\Versioning\RequiresPreviewFeaturesAttribute.cs" />
-  </ItemGroup>
-
   <ItemGroup>
     <PackageReference Include="Microsoft.IdentityModel.Tokens" Version="6.15.0" />
   </ItemGroup>