Upgrade to .NET 9 and update nuget packages

Dockerfile

@@ -1,13 +1,13 @@
 #See https://aka.ms/customizecontainer to learn how to customize your debug container and how Visual Studio uses this Dockerfile to build your images for faster debugging.
 
-FROM mcr.microsoft.com/dotnet/aspnet:8.0 AS base
+FROM mcr.microsoft.com/dotnet/aspnet:9.0 AS base
 WORKDIR /app
 EXPOSE 8080
 EXPOSE 8081
 RUN apt-get update && apt-get install -y curl
 USER app
 
-FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build
+FROM mcr.microsoft.com/dotnet/sdk:9.0 AS build
 ARG BUILD_CONFIGURATION=Release
 WORKDIR /src
 COPY ["src/WebApi/WebApi.csproj", "src/WebApi/"]