Update minor version to reflect added capability

Author: nblumhardt

src/Serilog.Sinks.File/Serilog.Sinks.File.csproj

@@ -1,8 +1,8 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <Description>Write Serilog events to text files in plain or JSON format.</Description>
-    <VersionPrefix>4.0.1</VersionPrefix>
+    <VersionPrefix>4.1.0</VersionPrefix>
     <Authors>Serilog Contributors</Authors>
     <TargetFrameworks>net45;netstandard1.3;netstandard2.0</TargetFrameworks>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>