update favicon
postmarketOS adapted a new brand colour palette, and the favicon still uses the old one.
There I chose #02ab59 or oklch(65% 0.169 152.42) as a colour with the same hue and maximum chroma as well, but bright enough to work in dark and light mode.
While updating the favicon to the new colour, I added a 48 px version, as that is another commonly requested favicon size.
Additionally, the 16 px and the 32 px version have its triangle gap doubled in width to make it more noticeable on those low resolutions.