Use recommended Compiler options

- Features: Strict
  Setting this ensures that we won't fall into compiler bugs when using latest features.

- LangVersion: Latest
  Setting this ensures that we always compile against latest version against the using SDK.

eng/Toolkit.Common.props

@@ -7,8 +7,9 @@
   </PropertyGroup>
 
   <PropertyGroup Label="Compile">
+    <Features>Strict</Features>
     <Nullable>Enable</Nullable>
-    <LangVersion>11.0</LangVersion>
+    <LangVersion>Latest</LangVersion>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
   </PropertyGroup>