Bump version to 5.12.0 in DotNetExtensions.csproj for release

Author: Necas209

DotNetExtensions/DotNetExtensions.csproj

@@ -13,7 +13,7 @@
     </PropertyGroup>
 
     <PropertyGroup>
-        <Version>5.11.5</Version>
+        <Version>5.12.0</Version>
         <Authors>Diogo Medeiros</Authors>
         <Company>Diogo Medeiros</Company>
         <Description>This is a collection of extension methods for .NET Core.</Description>