chore(deps): bump node in /images/docs

Bumps node from 21.5.0-alpine to 21.6.2-alpine.

---
updated-dependencies:
- dependency-name: node
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

images/docs/Dockerfile

@@ -2,7 +2,7 @@
 # image for creating the documentation
 ######################################
 
-FROM node:21.5.0-alpine as DOCS
+FROM node:21.6.2-alpine as DOCS
 
 ARG USER=docs
 ARG GROUP=docs