Merge pull request #104 from codimd/dependabot/docker/alpine/node-14.4.0-alpine

Bump node from 12.16.2-alpine to 14.4.0-alpine in /alpine

alpine/Dockerfile

-FROM node:12.16.2-alpine
+FROM node:14.4.0-alpine
 
 # Build arguments to change source url, branch or tag
 ARG CODIMD_REPOSITORY=https://github.com/codimd/server.git