Bump roslyn dependency, move to 5.0 analyzer

Author: kzu

src/Extensions.CodeAnalysis/Extensions.CodeAnalysis.csproj

@@ -3,12 +3,12 @@
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
     <IsRoslynComponent>true</IsRoslynComponent>
-    <PackFolder>analyzers/dotnet/roslyn4.0/cs</PackFolder>
+    <PackFolder>analyzers/dotnet/roslyn5.0/cs</PackFolder>
   </PropertyGroup>
 
   <ItemGroup>
     <PackageReference Include="NuGetizer" Version="1.4.7" PrivateAssets="all" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.0.1" Pack="false" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="5.0.0" Pack="false" />
     <PackageReference Include="PolySharp" Version="1.15.0" PrivateAssets="All" />
     <PackageReference Include="ThisAssembly.Resources" Version="2.1.2" PrivateAssets="all" />
   </ItemGroup>