Update ReadMe and NuGet package

Author: Giorgi

.github/sponsors/dapper-plus-sponsor.png

@@ -3,6 +3,15 @@
 [![NuGet Downloads](https://img.shields.io/nuget/dt/Math-Expression-Evaluator?style=for-the-badge)](https://www.nuget.org/packages/Math-Expression-Evaluator/)
 [![NuGet Version](https://img.shields.io/nuget/v/Math-Expression-Evaluator?style=for-the-badge)](https://www.nuget.org/packages/Math-Expression-Evaluator/)
 
+
+## Sponsors
+
+[Entity Framework Extensions](https://entityframework-extensions.net/) and [Dapper Plus](https://dapper-plus.net/) are major sponsors and are proud to contribute to the development of Math Expression Evaluator.
+
+[![Entity Framework Extensions - Sponsor](.github/sponsors/entity-framework-extensions-sponsr.png)](https://entityframework-extensions.net/bulk-insert)
+
+[![Dapper Plus - Sponsor](.github/sponsors/dapper-plus-sponsor.png)](https://dapper-plus.net/bulk-insert)
+
 ## Usage
 
 Math Expression Evaluator is a library for evaluating simple mathematical expressions. It supports simple expressions such as `2.5+5.9`, `17.89-2.47+7.16`, `5/2/2+1.5*3+4.58`, expressions with parentheses `(((9-6/2)*2-4)/2-6-1)/(2+24/(2+4))` and expressions with variables:

.github/sponsors/entity-framework-extensions-sponsr.png

@@ -15,11 +15,16 @@
     <Authors>Giorgi Dalakishvili</Authors>
     <PackageId>Math-Expression-Evaluator</PackageId>
     <Company>Giorgi Dalakishvili</Company>
+    <Deterministic>true</Deterministic>
+    <ContinuousIntegrationBuild Condition="'$(Configuration)'=='Release'">True</ContinuousIntegrationBuild>
     <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
-    <PackageProjectUrl>https://github.com/Giorgi/Math-Expression-Evaluator</PackageProjectUrl>
     <RepositoryUrl>https://github.com/Giorgi/Math-Expression-Evaluator</RepositoryUrl>
+    <PackageIcon>Icon.png</PackageIcon>
+    <PackageReadmeFile>README.md</PackageReadmeFile>
     <PackageTags>Math Expression Evaluator</PackageTags>
+    <PackageProjectUrl>https://github.com/Giorgi/Math-Expression-Evaluator</PackageProjectUrl>
     <PackageReleaseNotes>The library now targets .NET Standard 2.0</PackageReleaseNotes>
+    <PackageLicenseExpression>Apache-2.0</PackageLicenseExpression>
     <RepositoryType>git</RepositoryType>
   </PropertyGroup>
 
@@ -41,4 +46,15 @@
   <ItemGroup>
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="8.0.0" PrivateAssets="All" />
   </ItemGroup>
+
+  <ItemGroup>
+    <None Include="..\Icon.png">
+      <Pack>True</Pack>
+      <PackagePath></PackagePath>
+    </None>
+    <None Include="..\README.md">
+      <Pack>True</Pack>
+      <PackagePath></PackagePath>
+    </None>
+  </ItemGroup>
 </Project>