Update Node.js to v18 (#17)

renovate[bot] · renovate-bot · web-flow · commit 66a61fd30f82 · 2025-06-09T14:38:04.000+09:00
Co-authored-by: Renovate Bot &lt;bot@renovateapp.com&gt;
diff --git a/Dockerfile b/Dockerfile
@@ -1,4 +1,4 @@
-FROM node:16.13.0
+FROM node:18.2.0
 
 RUN apt-get update
 RUN apt-get upgrade -y
