update zcash image on sponsors page
On the sponsors page https://www.torproject.org/about/sponsors/ please update the image for zcash. (I created the zcash page yesterday, so it's not live yet. Here's a link to it: https://dip.torproject.org/bekeela/tpo/tree/master/content/about/sponsors/Zcash
In the images folder for the website, there is a zcash logo. Could it be changed so that it has the grey background like the other logos on the sponsors page?