Update node version for koa (#6227)

Author: JHyeok

frameworks/JavaScript/koa/koa-mysql.dockerfile

@@ -1,4 +1,4 @@
-FROM node:12.3.1-slim
+FROM node:14.15.1-slim
 
 COPY ./ ./
 

frameworks/JavaScript/koa/koa-postgres.dockerfile

@@ -1,4 +1,4 @@
-FROM node:12.3.1-slim
+FROM node:14.15.1-slim
 
 COPY ./ ./
 

frameworks/JavaScript/koa/koa.dockerfile

@@ -1,4 +1,4 @@
-FROM node:12.3.1-slim
+FROM node:14.15.1-slim
 
 COPY ./ ./
 

frameworks/JavaScript/koa/package.json

@@ -13,7 +13,7 @@
     "koa-router": "7.4.0",
     "mongoose": "5.7.5",
     "mysql2": "1.5.3",
-    "pg": "7.4.1",
+    "pg": "8.5.1",
     "pg-hstore": "2.3.2",
     "sequelize": "5.15.1"
   }