fix: report actual version instead of hardcoded 3.0.0-dev (#63)

The / endpoint was hardcoded to return 3.0.0-dev. Now uses the git tag version set via ldflags at build time.

Reviewed-on: #63
Co-authored-by: Ben Vincent <ben@unkin.net>
Co-committed-by: Ben Vincent <ben@unkin.net>

Dockerfile

@@ -9,7 +9,8 @@ RUN go mod download
 
 COPY . .
 
-RUN CGO_ENABLED=0 go build -ldflags="-s -w" -o artifactapi ./cmd/artifactapi
+ARG VERSION=dev
+RUN CGO_ENABLED=0 go build -ldflags="-s -w -X main.version=${VERSION}" -o artifactapi ./cmd/artifactapi
 
 FROM gcr.io/distroless/static-debian12:nonroot