Update dotnet monorepo to v9

Author: renovate[bot]

Dockerfile

@@ -1,4 +1,4 @@
-FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build-env
+FROM mcr.microsoft.com/dotnet/sdk:9.0 AS build-env
 
 WORKDIR /app
 
@@ -9,7 +9,7 @@ COPY Codingteam.Site ./Codingteam.Site/
 RUN dotnet build --no-restore --configuration Release Codingteam.Site
 RUN dotnet publish --no-build --configuration Release --output publish Codingteam.Site
 
-FROM mcr.microsoft.com/dotnet/aspnet:8.0
+FROM mcr.microsoft.com/dotnet/aspnet:9.0
 WORKDIR /app
 
 COPY --from=build-env /app/publish .