Update Dockerfile

Author: bdovaz

Dockerfile

@@ -1,4 +1,5 @@
-FROM --platform=$BUILDPLATFORM mcr.microsoft.com/dotnet/sdk:8.0-preview AS build
+FROM --platform=$BUILDPLATFORM mcr.microsoft.com/dotnet/sdk:7.0 AS build
+ARG TARGETARCH
 WORKDIR /app
 
 RUN mkdir -p src/UnityNuGet && mkdir -p src/UnityNuGet.Server && mkdir -p src/UnityNuGet.Tests
@@ -7,10 +8,10 @@ COPY src/*.sln src
 COPY src/UnityNuGet/*.csproj src/UnityNuGet
 COPY src/UnityNuGet.Server/*.csproj src/UnityNuGet.Server
 COPY src/UnityNuGet.Tests/*.csproj src/UnityNuGet.Tests
-RUN dotnet restore src
+RUN dotnet restore src -a $TARGETARCH
 
 COPY . ./
-RUN dotnet publish src -c Release -o /app/src/out
+RUN dotnet publish src -a $TARGETARCH -c Release -o /app/src/out
 
 # Build runtime image
 FROM mcr.microsoft.com/dotnet/aspnet:7.0