upgrade node

README.md

@@ -43,10 +43,12 @@ Harbor settings are passed to the container at runtime, so changing them needs a
 ## Container (plain Docker)
 
 ```sh
-docker build -t homepage --build-arg SITE_URL=https://example.com .
-docker run -p 8080:8080 \
-  -e HARBOR_URL=https://registry.example.com \
-  homepage
+docker build -t homepage \
+  --build-arg SITE_URL=https://example.com \
+  --build-arg HARBOR_URL=https://registry.example.com \
+  .
+docker run -p 8080:8080 homepage
+# HARBOR_URL is baked in as a default env var; override it with -e HARBOR_URL=... if needed.
 # optional robot account for non-public projects:
 #   -e HARBOR_USERNAME='robot$showcase' -e HARBOR_PASSWORD=...
 ```