Fix dotnet version in actions

Author: theepicmixer

.github/workflows/dotnet.yml

@@ -21,7 +21,7 @@ jobs:
     - name: Setup .NET
       uses: actions/setup-dotnet@v4
       with:
-        dotnet-version: 8.0.x
+        dotnet-version: 9.0.x
     - name: Setup GitVersion
       run: dotnet tool install GitVersion.Tool --global --add-source https://api.nuget.org/v3/index.json
     - name: RunGitVersion

src/Bdziam.DynamicColor.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net9.0</TargetFramework>
+    <TargetFramework>net9.0;net8.0;net7.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
   </PropertyGroup>