Update dependencies

@babel/core           7.12.3  →   7.12.9
 @babel/preset-env     7.12.1  →   7.12.7
 @babel/preset-react   7.12.1  →   7.12.7
 autoprefixer         ^10.0.1  →  ^10.0.4
 babel-loader          ^8.1.0  →   ^8.2.2
 gulp-sourcemaps       ^2.6.5  →   ^3.0.0
 jsonfile              ^6.0.1  →   ^6.1.0
 node-sass            ^4.14.1  →   ^5.0.0
 postcss               ^8.1.4  →  ^8.1.14
 semver                ^7.3.2  →   ^7.3.4
 sharp                ^0.26.2  →  ^0.26.3
 svelte               ^3.29.4  →  ^3.31.0
 ts-loader             ^8.0.7  →  ^8.0.11
 typescript             4.0.5  →    4.1.2
 webpack               ^5.3.0  →   ^5.9.0
 webpack-stream         6.1.0  →    6.1.1
 yargs                ^16.1.0  →  ^16.1.1
 mocha                 ^8.2.0  →   ^8.2.1

Author: enzy