v0.18.0 raw and json formatter improvements, dockerfile, go bump to 1.27.1

Dockerfile

@@ -0,0 +1,40 @@
+# Builder pin and go.mod directive are the same patch release deliberately;
+# an older builder reports the mismatch only after downloading the module graph.
+ARG GO_VERSION=1.27.1
+
+FROM docker.io/library/golang:${GO_VERSION}-alpine AS build
+
+# Git supplies Go's VCS build information; only /out/logwisp crosses stages.
+RUN apk add --no-cache git
+WORKDIR /src
+COPY go.mod go.sum ./
+RUN go mod download
+COPY . .
+
+ARG TARGETOS=linux
+ARG TARGETARCH=amd64
+ARG VERSION=dev
+ARG REVISION=unknown
+RUN CGO_ENABLED=0 GOOS=${TARGETOS} GOARCH=${TARGETARCH} \
+    go build -trimpath \
+      -ldflags="-s -w -X logwisp/internal/version.Version=${VERSION} -X logwisp/internal/version.GitCommit=${REVISION}" \
+      -o /out/logwisp ./cmd/logwisp
+
+FROM scratch
+
+ARG VERSION=dev
+ARG REVISION=unknown
+
+LABEL org.opencontainers.image.title="logwisp" \
+      org.opencontainers.image.description="Log transport: sources, flow, sinks" \
+      org.opencontainers.image.source="https://github.com/lixenwraith/logwisp" \
+      org.opencontainers.image.revision="${REVISION}" \
+      org.opencontainers.image.version="${VERSION}" \
+      org.opencontainers.image.licenses="BSD-3-Clause"
+
+COPY --from=build /out/logwisp /logwisp
+
+# Numeric identity is required in scratch and satisfies a restricted pod spec.
+USER 65532:65532
+
+ENTRYPOINT ["/logwisp"]