Add packages lock file to project

***NO_CI***

Author: josesimoes

nanoFramework.System.Text.Benchmark/nanoFramework.System.Text.Benchmark.nfproj

@@ -51,6 +51,9 @@
   <ItemGroup>
     <None Include="packages.config" />
   </ItemGroup>
+  <ItemGroup>
+    <Content Include="packages.lock.json" />
+  </ItemGroup>
   <Import Project="$(NanoFrameworkProjectSystemPath)NFProjectSystem.CSharp.targets" Condition="Exists('$(NanoFrameworkProjectSystemPath)NFProjectSystem.CSharp.targets')" />
   <ProjectExtensions>
     <ProjectCapabilities>

nanoFramework.System.Text/nanoFramework.System.Text.nfproj

@@ -58,6 +58,9 @@
   <ItemGroup>
     <AdditionalFiles Include="..\.sonarlint\nanoframework_lib-nanoframework.system.text\CSharp\SonarLint.xml" Link="SonarLint.xml" />
   </ItemGroup>
+  <ItemGroup>
+    <Content Include="packages.lock.json" />
+  </ItemGroup>
   <ItemGroup>
     <Reference Include="mscorlib, Version=1.16.1.0, Culture=neutral, PublicKeyToken=c07d481e9758c731">
       <HintPath>..\packages\nanoFramework.CoreLibrary.1.16.1\lib\mscorlib.dll</HintPath>
@@ -77,4 +80,4 @@
     <Error Condition="!Exists('..\packages\Nerdbank.GitVersioning.3.7.115\build\Nerdbank.GitVersioning.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\Nerdbank.GitVersioning.3.7.115\build\Nerdbank.GitVersioning.targets'))" />
   </Target>
   <Import Project="..\packages\Nerdbank.GitVersioning.3.7.115\build\Nerdbank.GitVersioning.targets" Condition="Exists('..\packages\Nerdbank.GitVersioning.3.7.115\build\Nerdbank.GitVersioning.targets')" />
-</Project>
+</Project>