C#: do not use <PublicSign>true</PublicSign> on non-windows

csharp/compatibility_tests/v3.0.0/src/Google.Protobuf.Test/Google.Protobuf.Test.csproj

@@ -5,7 +5,6 @@
     <TargetFrameworks>net451;netcoreapp2.1</TargetFrameworks>
     <AssemblyOriginatorKeyFile>../../keys/Google.Protobuf.snk</AssemblyOriginatorKeyFile>
     <SignAssembly>true</SignAssembly>
-    <PublicSign Condition=" '$(OS)' != 'Windows_NT' ">true</PublicSign>
     <IsPackable>False</IsPackable>
   </PropertyGroup>
 

csharp/src/Google.Protobuf.Benchmarks/Google.Protobuf.Benchmarks.csproj

@@ -5,7 +5,6 @@
     <TargetFramework>netcoreapp3.1</TargetFramework>
     <AssemblyOriginatorKeyFile>../../keys/Google.Protobuf.snk</AssemblyOriginatorKeyFile>
     <SignAssembly>true</SignAssembly>
-    <PublicSign Condition=" '$(OS)' != 'Windows_NT' ">true</PublicSign>
     <IsPackable>False</IsPackable>
     <DebugType>pdbonly</DebugType>
     <DebugSymbols>true</DebugSymbols>

csharp/src/Google.Protobuf.Test.TestProtos/Google.Protobuf.Test.TestProtos.csproj

@@ -10,7 +10,6 @@
     <LangVersion>3.0</LangVersion>
     <AssemblyOriginatorKeyFile>../../keys/Google.Protobuf.snk</AssemblyOriginatorKeyFile>
     <SignAssembly>true</SignAssembly>
-    <PublicSign Condition=" '$(OS)' != 'Windows_NT' ">true</PublicSign>
     <IsPackable>False</IsPackable>
   </PropertyGroup>
 

csharp/src/Google.Protobuf.Test/Google.Protobuf.Test.csproj

@@ -4,7 +4,6 @@
     <TargetFrameworks>net451;netcoreapp2.1</TargetFrameworks>
     <AssemblyOriginatorKeyFile>../../keys/Google.Protobuf.snk</AssemblyOriginatorKeyFile>
     <SignAssembly>true</SignAssembly>
-    <PublicSign Condition=" '$(OS)' != 'Windows_NT' ">true</PublicSign>
     <IsPackable>False</IsPackable>
     <AllowUnsafeBlocks>True</AllowUnsafeBlocks>
   </PropertyGroup>

csharp/src/Google.Protobuf/Google.Protobuf.csproj

@@ -12,7 +12,6 @@
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <AssemblyOriginatorKeyFile>../../keys/Google.Protobuf.snk</AssemblyOriginatorKeyFile>
     <SignAssembly>true</SignAssembly>
-    <PublicSign Condition=" '$(OS)' != 'Windows_NT' ">true</PublicSign>
     <PackageTags>Protocol;Buffers;Binary;Serialization;Format;Google;proto;proto3</PackageTags>
     <PackageReleaseNotes>C# proto3 support</PackageReleaseNotes>
     <PackageProjectUrl>https://github.com/protocolbuffers/protobuf</PackageProjectUrl>