Move to centralized package management

PkmnLib.Dynamic/PkmnLib.Dynamic.csproj

@@ -2,9 +2,6 @@
 
     <PropertyGroup>
         <TargetFramework>netstandard2.1</TargetFramework>
-        <LangVersion>12</LangVersion>
-        <Nullable>enable</Nullable>
-        <ImplicitUsings>enable</ImplicitUsings>
     </PropertyGroup>
 
     <PropertyGroup Condition=" '$(Configuration)' == 'Debug' ">
@@ -16,8 +13,8 @@
     </PropertyGroup>
 
     <ItemGroup>
-        <PackageReference Include="System.Collections.Immutable" Version="8.0.0"/>
-        <PackageReference Include="System.Text.Json" Version="8.0.5"/>
+        <PackageReference Include="System.Collections.Immutable"/>
+        <PackageReference Include="System.Text.Json"/>
     </ItemGroup>
     <ItemGroup>
         <ProjectReference Include="..\PkmnLib.Static\PkmnLib.Static.csproj"/>