Atlassian brands
We have an outdated bitbucket icon in the set.

Atlassian has a nice [design website](https://atlassian.design) which [lists all logos](https://atlassian.design/resources/logo-library) for download which includes SVG versions.

Atlassian's [trademark policy](https://www.atlassian.com/legal/trademark) does not restrict the use of their logos as long as the logos are "sourced from an official Atlassian site" : 
> If you wish to use an Atlassian logo, the logo should be sourced from an official Atlassian site (e.g., [Atlassian press kit](https://www.atlassian.com/company/news/press-kit), [Atlassian design site](https://atlassian.design/guidelines/marketing/resources/logo-files), [Trello design site](https://design.trello.com/resources)), used without modification, and follow relevant usage guidelines (e.g., [Atlassian logo guidelines](https://atlassian.design/guidelines/brand/logos) and [Trello logo guidelines](https://design.trello.com/style/brand)).  

It would be nice to have all the Atlassian brand logos in Fork Awesome.