build(deps): bump node from 18-alpine to 21-alpine

Bumps node from 18-alpine to 21-alpine.

---
updated-dependencies:
- dependency-name: node
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Dockerfile

@@ -1,4 +1,4 @@
-FROM node:18-alpine@sha256:a315556d82ef54561e54fca7d8ee333382de183d4e56841dcefcd05b55310f46
+FROM node:21-alpine@sha256:a8beafd69068c05d09183e75b9aa679b520ba68f94b19c90d0da9f307f9f6565
 ARG UID=1000
 ARG GID=1000