Different logo for Riot Nightly

[dbkr]

So we can tell them apart

Split from #12452

[dreadnaut]

Out of nowhere, a "nightly" variation of the current logo:

SVG version (zipped, as GitHub does not accept SVG attachments.

[jryans]

We've decided this is not a blocker for cross-signing release.

[t3chguy]

Right now it looks like nightly has no icon at all however:

[turt2live]

@t3chguy sounds like a bug with our electron upgrade: #12518

[t3chguy]

I doubt it, all those reports are Linux caused by #12518 (comment)
I use Windows, after riot initializes and favico.js takes over it is fine, it is just the initial icon which is missing.

[turt2live]

It's also fine for me:

[t3chguy]

Is it fine for you the moment the app starts?