Fix missing nullable enable in Microsoft.Extensions.Logging.Abstractions ref (#53199)

diff --git a/src/libraries/Microsoft.Extensions.Logging.Abstractions/ref/Microsoft.Extensions.Logging.Abstractions.csproj b/src/libraries/Microsoft.Extensions.Logging.Abstractions/ref/Microsoft.Extensions.Logging.Abstractions.csproj
index 905c8b2..0086184 100644 (file)
--- a/src/libraries/Microsoft.Extensions.Logging.Abstractions/ref/Microsoft.Extensions.Logging.Abstractions.csproj
+++ b/src/libraries/Microsoft.Extensions.Logging.Abstractions/ref/Microsoft.Extensions.Logging.Abstractions.csproj
@@ -1,6 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;net461</TargetFrameworks>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="Microsoft.Extensions.Logging.Abstractions.cs" />