Remove unnecessary Mono.Options reference.

Author: yfakariya

src/mpu/mpu.csproj

@@ -40,11 +40,6 @@
     <Reference Include="System.XML" />
     <Reference Include="System.Xml.Linq" />
   </ItemGroup>
-  <ItemGroup>
-    <PackageReference Include="Mono.Options">
-      <Version>1.1</Version>
-    </PackageReference>
-  </ItemGroup>
   <ItemGroup>
     <Compile Include="..\CommonAssemblyInfo.cs">
       <Link>Properties\CommonAssemblyInfo.cs</Link>