mathias-an-author: add Mathias Brossard to the AUTHORS file
-Veracruz originated in the Distributed Systems and Security Research
-Group at Arm Research, and was originally designed and written by the
-*Veracruz Development Team*:
+Veracruz originated in the Systems (formerly Security) Research Group at Arm Research,
+and is designed and written by the *Veracruz Development Team*:
+- Mathias Brossard (mathias.brossard@arm.com)
- Basma El Gaabouri (basma.elgaabouri@arm.com)
- Christopher Haster (christopher.haster@arm.com)
- Derek Miller (derek.miller@arm.com)
