build: optimize binary size in Dockerfile

Dockerfile

@@ -1,7 +1,7 @@
 FROM golang:1.19 as build
 WORKDIR /build
 COPY . .
-RUN go build -o alpha main.go
+RUN go build -o alpha -a -gcflags=all="-l -B -wb=false" -ldflags="-w -s" main.go
 
 FROM scratch
 COPY --from=build /build/alpha ./alpha