Update node version for fastify (#6814)

Author: JHyeok

frameworks/JavaScript/fastify/fastify-mysql.dockerfile

@@ -1,4 +1,4 @@
-FROM node:14.17.5
+FROM node:16.9.1
 
 COPY ./ ./
 

frameworks/JavaScript/fastify/fastify-postgres.dockerfile

@@ -1,4 +1,4 @@
-FROM node:14.17.5
+FROM node:16.9.1
 
 COPY ./ ./
 

frameworks/JavaScript/fastify/fastify.dockerfile

@@ -1,4 +1,4 @@
-FROM node:14.17.5
+FROM node:16.9.1
 
 COPY ./ ./