Added multi-target build properties to target net8.0 and net9.0 SDKs.

Author: MrMatthewLayton

Directory.Build.props

@@ -1,15 +1,15 @@
 <Project>
     <PropertyGroup>
-        <TargetFramework>net9.0</TargetFramework>
+        <TargetFrameworks>net8.0;net9.0</TargetFrameworks>
         <LangVersion>13</LangVersion>
         <Nullable>enable</Nullable>
         <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
         <Authors>ONIXLabs</Authors>
         <NeutralLanguage>en</NeutralLanguage>
         <Copyright>Copyright © ONIXLabs 2020</Copyright>
         <RepositoryUrl>https://github.com/onix-labs/onixlabs-dotnet</RepositoryUrl>
-        <Version>11.0.0</Version>
-        <PackageVersion>11.0.0</PackageVersion>
-        <AssemblyVersion>11.0.0</AssemblyVersion>
+        <Version>11.1.0</Version>
+        <PackageVersion>11.1.0</PackageVersion>
+        <AssemblyVersion>11.1.0</AssemblyVersion>
     </PropertyGroup>
 </Project>

global.json

@@ -0,0 +1,7 @@
+{
+    "sdk": {
+        "version": "9.0.100",
+        "rollForward": "latestFeature",
+        "allowPrerelease": false
+    }
+}