在尝试完命令

npm install -g windows-build-tools@4.0.0

或者加host文件为

140.82.112.3 github.com
140.82.114.4 gist.github.com
185.199.108.153 assets-cdn.github.com
199.232.68.133 raw.githubusercontent.com
199.232.68.133 gist.githubusercontent.com
199.232.68.133 cloud.githubusercontent.com
199.232.68.133 camo.githubusercontent.com
199.232.68.133 avatars0.githubusercontent.com
199.232.68.133 avatars1.githubusercontent.com
199.232.68.133 avatars2.githubusercontent.com
199.232.68.133 avatars3.githubusercontent.com
199.232.68.133 avatars4.githubusercontent.com
199.232.68.133 avatars5.githubusercontent.com
199.232.68.133 avatars6.githubusercontent.com
199.232.68.133 avatars7.githubusercontent.com
199.232.68.133 avatars8.githubusercontent.com

仍然不行时，试试下面两条命令

npm install imagemin-pngquant@5.0.1 --save
npm install pngquant-bin@4.0.0 --save