docker file ARM fix

src/Tuitio/Dockerfile

@@ -1,11 +1,11 @@
 #See https://aka.ms/containerfastmode to understand how Visual Studio uses this Dockerfile to build your images for faster debugging.
 
-FROM mcr.microsoft.com/dotnet/aspnet:8.0 AS base
+FROM --platform=$BUILDPLATFORM mcr.microsoft.com/dotnet/aspnet:8.0 AS base
 WORKDIR /app
 EXPOSE 80
 
 # This stage is used to build the service project
-FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build
+FROM --platform=$BUILDPLATFORM mcr.microsoft.com/dotnet/sdk:8.0 AS build
 ARG BUILD_CONFIGURATION=Release
 WORKDIR /workspace
 COPY ["dependencies.props", "."]