ci: lowered docker image size by half by using alpine linux

Dockerfile

@@ -3,14 +3,14 @@ FROM mcr.microsoft.com/dotnet/sdk:9.0 AS build
 WORKDIR /App
 COPY . ./
 
-RUN apt update
-
 RUN dotnet restore
-RUN dotnet publish Platforms/Server -c Release -o out
+RUN dotnet publish Platforms/Server -c Release -r linux-musl-x64 --self-contained true -o out
 
-FROM mcr.microsoft.com/dotnet/runtime:9.0
+FROM alpine:latest
 
 WORKDIR /App
 COPY --from=build /App/out .
 
-ENTRYPOINT ["dotnet", "Server.dll"]
+RUN apk add --no-cache icu-libs
+
+ENTRYPOINT ["./Server"]