update assembly version

Author: smdn

src/Smdn.Net.SkStackIP/Smdn.Net.SkStackIP.csproj

@@ -5,7 +5,7 @@ SPDX-License-Identifier: MIT
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <TargetFrameworks>net8.0;net6.0;netstandard2.1</TargetFrameworks>
-    <VersionPrefix>1.3.0</VersionPrefix>
+    <VersionPrefix>1.4.0</VersionPrefix>
     <VersionSuffix></VersionSuffix>
     <PackageValidationBaselineVersion>1.0.0</PackageValidationBaselineVersion>
     <Nullable>enable</Nullable>