Edited readme with 3 updated browser icons. (#4414)
Edited readme with 3 updated browser icons. (#4414)

In the main readme file of axios, the icons for chrome, firefox and safari was not visible, which was giving a bit outdated vibes. I have updated all the three icons with the latest ones from  "https://www.iconfinder.com/icons/23799/firefox_icon" in 48px dimension. I hope now it looks good.

Co-authored-by: Jay <4f5661b92532aa65dc137cefa1d321b17b131199@gmail.com>
axios/axios,axios/axios,axios/axios