Update version.

src/Parbad/Parbad.csproj

@@ -3,7 +3,7 @@
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
     <LangVersion>latest</LangVersion>
-    <Version>3.0.0</Version>
+    <Version>3.1.0</Version>
     <Authors>Sina Soltani</Authors>
     <Description>Parbad is a free and open-source integrated online payment library which helps developers and site owners to add the online payment ability to their websites. It provides an easy solution to perform payment request, verify a payment and refund a paid payment.
 It supports the most known online payment providers in Iran such as Mellat, Melli, Parsian, Tejarat, Saman, Pasargad and Asan Pardakht.