fixup docker file

Dockerfile

@@ -1,16 +1,8 @@
-FROM golang:latest AS builder
-WORKDIR $GOPATH/src/github.com/BeryJu/saml-test-sp
-COPY . .
-ENV CGO_ENABLED=0
-ENV GOOS=linux
-ENV GOARCH=amd64
-RUN go build -v -o /go/bin/saml-test-sp
-
-FROM alpine
-COPY --from=builder /go/bin/saml-test-sp /saml-test-sp
+FROM docker.io/library/alpine:3.17.3
+RUN apk add --no-cache ca-certificates
+COPY saml-test-sp /
 EXPOSE 9009
 WORKDIR /web-root
 ENV SP_BIND=0.0.0.0:9009
 HEALTHCHECK --interval=5s --start-period=1s CMD [ "wget", "--spider", "http://localhost:9009/health" ]
-CMD [ "/saml-test-sp" ]
 ENTRYPOINT [ "/saml-test-sp" ]