I'm not proficient in the program, but it can be done in Inkscape. I'm sure someone will swoop in and explain it in inkscape. One thing I noticed when I zoomed in on the image is that there is an impreciseness with those squares in your image. Whoever made this image used alternating row width of 7 pixels and 8 pixels which makes it slightly more involved of a process when making a grid for the pixelated effect.
The low down, quick way is to use image tracing in Adobe Illustrator, it literally takes less than a minute compared to the more involved process of recreating the pixels using a grid. I'm not 100% sure if bitmap tracing in Inkscape will yield the same result.
In any case the process in Illustrator is to import the image and then use the image trace with roughly the same settings as the image below. It will yield a rigid pixel-like effect.
The effect zoomed in. For most of the effect there will be no abnormalities.
However, certain areas you will need to fix the paths manually because they are slightly off.