Update target framework from net7 to net8.

Author: Konard

csharp/Platform.Data.Triplets/Platform.Data.Triplets.csproj

@@ -24,10 +24,7 @@
     <IncludeSymbols>true</IncludeSymbols>
     <SymbolPackageFormat>snupkg</SymbolPackageFormat>
     <LangVersion>latest</LangVersion>
-    <PackageReleaseNotes>.NET 5 support is added.
-Platform.Data.Sequences 0.0.2 dependency is added.
-Platform.Data dependency is updated from 0.3.0 to 0.5.0.
-Microsoft.NETFramework.ReferenceAssemblies dependency is updated from 1.0.0 to 1.0.2</PackageReleaseNotes>
+    <PackageReleaseNotes>Update target framework from net7 to net8.</PackageReleaseNotes>
     <Nullable>enable</Nullable>
   </PropertyGroup>