[FFmpeg-devel] Update credits.

[Tae Wong]

You will need to add accented letters in the credits, for the
following names. Then, update Reynaldo Verdejo’s name.

Arpad Gereoffy = Árpád Gereöffy
Reimar Doeffinger = Reimar Döffinger
Reynaldo Verdejo = Reynaldo H. Verdejo Pinochet

Also, you should add the maintainers to the credits. Here are they.

Anssi Hannula
Anton Khirnov
Attila Kinali
Baptiste Coudurier
Ben Littler
Benoit Fouet
Clément Bœsch
Daniel Verkamp
Diego Biurrun
Gwenole Beauchesne
Jaikrishnan Menon
Justin Ruggles
Lou Logan
Luca Barbato
Nicolas George
Panagiotis Issaris
Reinhard Tartler
Robert Swain
Stephan Hilb
Tomas Härdin