Enhance workflow (#51)

Co-authored-by: CrazyMax <crazy-max@users.noreply.github.com>

hack/vendor.Dockerfile

@@ -0,0 +1,23 @@
+# syntax=docker/dockerfile:1.2
+ARG NODE_VERSION
+
+FROM node:${NODE_VERSION}-alpine AS base
+RUN apk add --no-cache git
+WORKDIR /src
+
+FROM base AS vendored
+RUN --mount=type=bind,target=.,rw \
+  --mount=type=cache,target=/src/node_modules \
+  yarn install && mkdir /out && cp yarn.lock /out
+
+FROM scratch AS update
+COPY --from=vendored /out /
+
+FROM vendored AS validate
+RUN --mount=type=bind,target=.,rw \
+  git add -A && cp -rf /out/* .; \
+  if [ -n "$(git status --porcelain -- yarn.lock)" ]; then \
+    echo >&2 'ERROR: Vendor result differs. Please vendor your package with "docker buildx bake vendor-update"'; \
+    git status --porcelain -- yarn.lock; \
+    exit 1; \
+  fi