chore: change base image for template base dockerfile [skip ci]

Author: denolfe

templates/_template/Dockerfile

@@ -1,6 +1,7 @@
+# To use this Dockerfile, you have to set `output: 'standalone'` in your next.config.mjs file.
 # From https://github.com/vercel/next.js/blob/canary/examples/with-docker/Dockerfile
 
-FROM node:18-alpine AS base
+FROM node:22.12.0-alpine AS base
 
 # Install dependencies only when needed
 FROM base AS deps

templates/blank/Dockerfile

@@ -1,6 +1,7 @@
+# To use this Dockerfile, you have to set `output: 'standalone'` in your next.config.mjs file.
 # From https://github.com/vercel/next.js/blob/canary/examples/with-docker/Dockerfile
 
-FROM node:18-alpine AS base
+FROM node:22.12.0-alpine AS base
 
 # Install dependencies only when needed
 FROM base AS deps