doc: update README (#61)

* doc: update README

Signed-off-by: Jian Zeng <anonymousknight96@gmail.com>

* chore: update Dockerfile-server

Signed-off-by: Jian Zeng <anonymousknight96@gmail.com>

---------

Signed-off-by: Jian Zeng <anonymousknight96@gmail.com>

Author: knight42

README.md

@@ -105,6 +105,11 @@ kubectl relay -V
 
 ## Usage
 
+> [!NOTE]
+> Starting from version v0.1.2, `krelay` attempts to tunnel SPDY through websocket, in line with how `kubectl port-forward` works.
+>
+> This behavior can be disabled by setting the environment variable `KUBECTL_PORT_FORWARD_WEBSOCKETS` to `false`.
+
 ```bash
 # Listen on port 8080 locally, forwarding data to the port named "http" in the service
 kubectl relay service/my-service 8080:http

manifests/Dockerfile-server

@@ -1,9 +1,11 @@
 FROM golang:1.22.5 AS builder
 WORKDIR /workspace
-ADD . .
-RUN CGO_ENABLED=0 go build -trimpath -ldflags '-w -s' -o krelay-server ./cmd/server
+RUN --mount=type=cache,target=/go/pkg/mod \
+    --mount=type=cache,target=/root/.cache/go-build \
+    --mount=target=. \
+  CGO_ENABLED=0 go build -trimpath -ldflags '-w -s' -o /tmp/server ./cmd/server
 
 FROM gcr.io/distroless/static:nonroot
 LABEL maintainer="Jian Zeng <anonymousknight96@gmail.com>"
-COPY --from=builder /workspace/krelay-server /server
+COPY --from=builder /tmp/server /server
 ENTRYPOINT ["/server"]