Download the lastest wget binary for windows from 

https://eternallybored.org/misc/wget/
(they are available as a zip with documentation, or just an exe)

If you downloaded the zip, extract all (if windows built in zip 
utility gives an error, use 7-zip). Rename the file wget64.exe 
to wget.exe if necessary. Move wget.exe to your Git\mingw64\bin\.