fix: downgrade .NET version from 10.0.x to 9.0.x in workflow and project file

Author: jakubkozera

.github/workflows/deploy-sample-api.yml

@@ -10,7 +10,7 @@ on:
 env:
   AZURE_WEBAPP_NAME: openapi-ui
   AZURE_WEBAPP_PACKAGE_PATH: "./src/c-sharp/JakubKozera.OpenApiUi.Sample"
-  DOTNET_VERSION: "10.0.x"
+  DOTNET_VERSION: "9.0.x"
 
 jobs:
   build-and-deploy:

src/c-sharp/JakubKozera.OpenApiUi.Sample/JakubKozera.OpenApiUi.Sample.csproj

@@ -1,6 +1,5 @@
-<Project Sdk="Microsoft.NET.Sdk.Web">
-  <PropertyGroup>
-    <TargetFramework>net10.0</TargetFramework>
+<Project Sdk="Microsoft.NET.Sdk.Web">  <PropertyGroup>
+    <TargetFramework>net9.0</TargetFramework>
     <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>