rules: [
{
test: /\.(sa|sc|c)ss$/,
use: [
devMode ? "style-loader" : MiniCssExtractPlugin.loader,
"css-loader",
"less-loader",
"sass-loader",
],
},]

　　

  改为 （增加正则匹配）  

rules: [
{
test: /\.(le|sa|sc|c)ss$/,
use: [
devMode ? "style-loader" : MiniCssExtractPlugin.loader,
"css-loader",
"less-loader",
"sass-loader",
],
},