simplify dockerfile

Dockerfile

@@ -5,13 +5,8 @@ WORKDIR /app
 EXPOSE 80
 EXPOSE 443
 
-FROM mcr.microsoft.com/dotnet/core/sdk:3.1-buster AS build
+FROM mcr.microsoft.com/dotnet/core/sdk:3.1-buster AS publish
 COPY ./src/ ./src/
-RUN dotnet restore "/src/BirdsiteLive/BirdsiteLive.csproj"
-RUN dotnet restore "/src/BSLManager/BSLManager.csproj"
-RUN dotnet build "/src/BirdsiteLive/BirdsiteLive.csproj" -c Release -o /app/build
-
-FROM build AS publish
 RUN dotnet publish "/src/BirdsiteLive/BirdsiteLive.csproj" -c Release -o /app/publish
 RUN dotnet publish "/src/BSLManager/BSLManager.csproj" -r linux-x64 --self-contained true -p:PublishSingleFile=true -p:IncludeAllContentForSelfExtract=true -c Release -o /app/publish