chore(deps): update node.js to v24 (#65)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

build-images.sh

@@ -21,7 +21,7 @@ container=$(buildah from scratch)
 # Reuse existing nodebuilder-roundcubemail container, to speed up builds
 if ! buildah containers --format "{{.ContainerName}}" | grep -q nodebuilder-roundcubemail; then
     echo "Pulling NodeJS runtime..."
-    buildah from --name nodebuilder-roundcubemail -v "${PWD}:/usr/src:Z" docker.io/library/node:18-slim
+    buildah from --name nodebuilder-roundcubemail -v "${PWD}:/usr/src:Z" docker.io/library/node:24-slim
 fi
 
 echo "Build static UI files with node..."