Merge pull request #278 from notion-dotnet/set-version-prefix-to-3-1-0

Set version prefix to 3.1.0-preview

Author: KoditkarVedant

Src/Notion.Client/Notion.Client.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <VersionPrefix>3.0.0-preview</VersionPrefix>
+    <VersionPrefix>3.1.0-preview</VersionPrefix>
     <TargetFramework>netstandard2.0</TargetFramework>
     <LangVersion>7.3</LangVersion>