Bump version to v4.3.1 (#599)

Bump version to v4.3.1
* NodaTime v3.2.0 (released  yesterday) brings some welcome changes
* Update Ical.Net.csproj to use NodaTime 3.2.0 instead of 3.1.12.
* Replace Ical.Net.nuspec with Directory.Build.props
* Remove unnecessary nuget dependencies, so NodaTime is again the only one

Resolves #596

Ical.Net/Directory.Build.props

@@ -0,0 +1,42 @@
+<Project>
+    <PropertyGroup>
+        <PackageId>Ical.Net</PackageId>
+        <Title>Ical.Net</Title>
+        <Authors>ical-org maintainers and contributors</Authors>
+        <Owners>ical-org</Owners>
+        <PackageRequireLicenseAcceptance>false</PackageRequireLicenseAcceptance>
+        <Description>The most popular iCalendar (RFC 5545) class library for .NET.</Description>
+        <PackageProjectUrl>https://github.com/ical-org/ical.net</PackageProjectUrl>
+        <PackageLicenseExpression>MIT</PackageLicenseExpression>
+        <PackageReleaseNotes>https://github.com/ical-org/ical.net/blob/main/release-notes.md</PackageReleaseNotes>
+        <PackageTags>iCal Calendar icalendar ics outlook events rfc-5545 rfc-2445 dday</PackageTags>
+        <PackageIcon>assets/icon.png</PackageIcon>
+        <PackageReadmeFile>assets/readme.md</PackageReadmeFile>
+    </PropertyGroup>
+    <ItemGroup>
+        <None Include="..\readme.md">
+            <Pack>true</Pack>
+            <PackagePath>assets/readme.md</PackagePath>
+        </None>
+        <None Include="..\assets\icon.png">
+            <Pack>true</Pack>
+            <PackagePath>assets/icon.png</PackagePath>
+        </None>
+        <None Update=".\bin\Release\net8.0\**\*">
+            <Pack>true</Pack>
+            <PackagePath>lib\net8.0\</PackagePath>
+        </None>
+        <None Update=".\bin\Release\net6.0\**\*">
+            <Pack>true</Pack>
+            <PackagePath>lib\net6.0\</PackagePath>
+        </None>
+        <None Update=".\bin\Release\netstandard2.1\**\*">
+            <Pack>true</Pack>
+            <PackagePath>lib\netstandard2.1\</PackagePath>
+        </None>
+        <None Update=".\bin\Release\netstandard2.0\**\*">
+            <Pack>true</Pack>
+            <PackagePath>lib\netstandard2.0\</PackagePath>
+        </None>
+    </ItemGroup>
+</Project>

Ical.Net/Ical.Net.csproj

@@ -1,16 +1,15 @@
 <Project Sdk="Microsoft.NET.Sdk" ToolsVersion="15.0">
     <PropertyGroup>
         <TargetFrameworks>net8.0;net6.0;netstandard2.1;netstandard2.0</TargetFrameworks>
-        <NuspecProperties>version=$(Version)</NuspecProperties>
         <SignAssembly>true</SignAssembly>
         <AssemblyOriginatorKeyFile>..\IcalNetStrongnameKey.snk</AssemblyOriginatorKeyFile>
     </PropertyGroup>
     <ItemGroup>
-        <PackageReference Include="NodaTime" Version="3.1.*" />
+        <PackageReference Include="NodaTime" Version="3.2.0" />
     </ItemGroup>
     <ItemGroup>
         <AssemblyAttribute Include="System.Runtime.CompilerServices.InternalsVisibleToAttribute">
             <_Parameter1>Ical.Net.Tests, PublicKey=0024000004800000940000000602000000240000525341310004000001000100a1f790f70176d52efbd248577bdb292be2d0acc62f3227c523e267d64767f207f81536c77bb91d17031a5afbc2d69cd3b5b3b9c98fa8df2cd363ec90a08639a1213ad70079eff666bcc14cf6574b899f4ad0eac672c8f763291cb1e0a2304d371053158cb398b2e6f9eeb45db7d1b4d2bbba1f985676c5ca4602fab3671d34bf</_Parameter1>
         </AssemblyAttribute>
     </ItemGroup>
-</Project>
+</Project>