Generate version during compilation

Dockerfile

@@ -8,9 +8,10 @@ ENV CGO_ENABLED=0
 RUN set -ex \
     && apk add git build-base \
     && export COMMIT=$(git rev-parse --short HEAD) \
+    && export VERSION=$(go run ./cmd/internal/read_tag) \
     && go build -v -trimpath -tags with_quic,with_wireguard,with_acme \
         -o /go/bin/sing-box \
-        -ldflags "-s -w -buildid=" \
+        -ldflags "-X \"github.com/sagernet/sing-box/constant.Version=$VERSION\" -s -w -buildid=" \
         ./cmd/sing-box
 FROM alpine AS dist
 LABEL maintainer="nekohasekai <contact-git@sekai.icu>"