feat(agent): add updater-agent binary and ship it in the image

Dockerfile

@@ -8,15 +8,17 @@ 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=${BUILD_TIME}" \
-    -o /out/package-updater ./cmd/server
+RUN for cmd in server:package-updater agent:updater-agent; do \
+      CGO_ENABLED=0 go build \
+        -ldflags="-s -w \
+          -X main.version=${VERSION} \
+          -X main.commit=${COMMIT} \
+          -X main.buildTime=${BUILD_TIME}" \
+        -o /out/${cmd#*:} ./cmd/${cmd%%:*} || exit 1; \
+    done
 
 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/
+COPY --from=build /out/ /usr/local/bin/
 EXPOSE 8080
 ENTRYPOINT ["/usr/local/bin/package-updater"]