Fix Dockerfile issues

* Add ldflags to embed version at build time
* Revert to using scratch image instead of debian base to reduce size and build time

Dockerfile

@@ -3,24 +3,10 @@ FROM golang:1.22 AS builder
 WORKDIR /app
 COPY . .
 
-RUN CGO_ENABLED=0 go build -o /app/mobius-hotline-bot . && chmod a+x /app/mobius-hotline-bot
+RUN CGO_ENABLED=0 go build -ldflags "-X main.version=$(git describe --exact-match --tags)" -o /app/mobius-hotline-bot . && chmod a+x /app/mobius-hotline-bot
 
-FROM debian:stable-slim
-
-# Change these as you see fit. This makes bind mounting easier so you don't have to edit bind mounted config files as root.
-ARG USERNAME=hl-bot
-ARG UID=1001
-ARG GUID=1001
-
-RUN apt-get update \
- && apt-get install -y --no-install-recommends ca-certificates
-
-RUN update-ca-certificates
+FROM scratch
 
 COPY --from=builder /app/mobius-hotline-bot /app/mobius-hotline-bot
 
-RUN useradd -d /app -u ${UID} ${USERNAME}
-RUN chown -R ${USERNAME}:${USERNAME} /app
-
-USER ${USERNAME}
 ENTRYPOINT ["/app/mobius-hotline-bot"]