vue.config.js Alias configuration file path in webpack

## Create vue.config.js file in the vue project

alias: the meaning of configuration alias

Configure the relevant properties in vue.config.js as follows

Here, 'src' and 'common' can be defined at will (a small hint that once this file is modified, the project must be restarted otherwise it will not take effect)

After the definition, it is very convenient to introduce it without having to write the absolute path and relative path all the time