build: multi-stage Dockerfile with build info ldflags

Dockerfile

@@ -0,0 +1,22 @@
+# syntax=docker/dockerfile:1.7
+
+FROM golang:1.23-alpine AS build
+WORKDIR /src
+COPY go.mod go.sum ./
+RUN go mod download
+COPY . .
+ARG VERSION=dev
+ARG COMMIT=unknown
+ARG BUILD_TIME=unknown
+RUN CGO_ENABLED=0 go build \
+    -ldflags="-s -w \
+      -X main.version=${VERSION} \
+      -X main.commit=${COMMIT} \
+      -X main.buildTime=${BUILD_TIME}" \
+    -o /out/package-updater ./cmd/server
+
+FROM alpine:3.20
+RUN apk add --no-cache docker-cli docker-cli-compose ca-certificates wget
+COPY --from=build /out/package-updater /usr/local/bin/
+EXPOSE 8080
+ENTRYPOINT ["/usr/local/bin/package-updater"]