fix docker build

Author: its-felix

Dockerfile

@@ -1,10 +1,14 @@
-FROM golang:1.19
-WORKDIR /go/src/github.com/gw2auth/http-echo/
+FROM golang:1.26 AS builder
+
+WORKDIR /build
+
 COPY go.mod ./
-COPY main.go ./
-RUN CGO_ENABLED=0 go build -a -o app
+RUN go mod download
+
+COPY ../.. ./
+RUN CGO_ENABLED=0 go build -o http-echo
 
-FROM alpine:latest
-WORKDIR /root/
-COPY --from=0 /go/src/github.com/gw2auth/http-echo/app ./app
-CMD ["/root/app"]
+FROM scratch
+COPY --from=builder /build/http-echo /http-echo
+EXPOSE 8080
+ENTRYPOINT ["/http-echo"]