update assembly version

Author: smdn

src/Smdn.Net.MuninNode/Smdn.Net.MuninNode.csproj

@@ -5,7 +5,7 @@ SPDX-License-Identifier: MIT
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <TargetFrameworks>netstandard2.1;net8.0</TargetFrameworks>
-    <VersionPrefix>2.0.0</VersionPrefix>
+    <VersionPrefix>2.1.0</VersionPrefix>
     <VersionSuffix></VersionSuffix>
     <PackageValidationBaselineVersion>2.0.0</PackageValidationBaselineVersion>
     <RootNamespace/> <!-- empty the root namespace so that the namespace is determined only by the directory name, for code style rule IDE0030 -->