[Dependencies] Fix SDL3-CS project flags;

Author: LittleCodingFox

Dependencies/build/dotnet/SDL3-CS.csproj

@@ -6,6 +6,9 @@
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <Configurations>Release;Debug</Configurations>
     <EnableDefaultCompileItems>false</EnableDefaultCompileItems>
+	<ImplicitUsings>enable</ImplicitUsings>
+	<Nullable>enable</Nullable>
+	<AllowUnsafeBlocks>true</AllowUnsafeBlocks>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <PlatformTarget>AnyCPU</PlatformTarget>