Support for 2.13.9

[Sebastian Peter]

Support for scala 2.13.9 would be wonderful at some point in time.

[Henri Cook]

I've raised #680 but it's the first time I've contributed to this project and I can't then do releases so hopefully the merge gods look soon 🙏🏻

[Greg Oledzki]

Thank you @henricook for the contribution.

I've just triggered the release of 1.4.16 with this. Ping me here if it it doesn't work for you.