* Update Basic Machine Learning Blog Course

Machine learn cơ bản blog by Vũ Hữu Tiệp

* Add blank line to seperate section.

* Add blank line to seperate section.

* Update courses/free-courses-vi.md
Co-authored-by: NDavid Ordás <3125580+davorpa@users.noreply.github.com>
Co-authored-by: NEric Hellman <eric@hellman.net>
Co-authored-by: NDavid Ordás <3125580+davorpa@users.noreply.github.com>