Stepping down as aarch64 maintainer

[Marcus Shawcroft]

Hello Newlib Community,

Many years have past since I actively worked on newlib, so this email is long over due. I’ll be leaving Arm shortly so this seems like a good time to formerly step down as an AArch64 maintainer. It has been a privilege to contribute to newlib and to work alongside the  community. I wish the project all best going forward.

Cheers
/Marcus