7.4    Pulumi hereby grants you a limited, non-exclusive, royalty-free, non-transferable license, with no right to sub-license, to display the Pulumi trademarks and/or logos (“Marks”) for the sole purpose of promoting or advertising that you use the Pulumi Services and solely in accordance with Pulumi’s then current Trademark Usage Guidelines, which may be found at https://www.pulumi.com/trademark. You agree that all goodwill generated through your use of the Pulumi Marks shall inure to the benefit of Pulumi.

I think it's safe to assume I can use Pulumi logo in diagram on GitHub for a GPLv2 project using Pulumi. If not so, please let me know.