MAINTAINERS: Add myself as vvc maintainer

My OpenPGP key is available at

https://keys.openpgp.org/vks/v1/by-fingerprint/34E248D6B7DF476970C7330403A84C6A098F2C6B

and

https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x34e248d6b7df476970c7330403a84c6a098f2c6b
Signed-off-by: Frank Plowman <post@frankplowman.com>

MAINTAINERS

@@ -267,7 +267,7 @@ Codecs:
   vp8                                   David Conrad, Ronald Bultje
   vp9                                   Ronald Bultje
   vqavideo.c                            Mike Melanson
-  vvc                               [2] Nuo Mi, Wu Jianhua
+  vvc                               [2] Nuo Mi, Wu Jianhua, Frank Plowman
   wmaprodec.c                           Sascha Sommer
   wmavoice.c                            Ronald S. Bultje
   wmv2.c                                Michael Niedermayer
@@ -587,6 +587,7 @@ Benoit Fouet                  B22A 4F4F 43EF 636B BB66 FCDC 0023 AE1E 2985 49C8
 Clément Bœsch                 52D0 3A82 D445 F194 DB8B 2B16 87EE 2CB8 F4B8 FCF9
 Daniel Verkamp                78A6 07ED 782C 653E C628 B8B9 F0EB 8DD8 2F0E 21C7
 FFmpeg release signing key    FCF9 86EA 15E6 E293 A564 4F10 B432 2F04 D676 58D8
+Frank Plowman                 34E2 48D6 B7DF 4769 70C7 3304 03A8 4C6A 098F 2C6B
 Ganesh Ajjanagadde            C96A 848E 97C3 CEA2 AB72 5CE4 45F9 6A2D 3C36 FB1B
 Gwenole Beauchesne            2E63 B3A6 3E44 37E2 017D 2704 53C7 6266 B153 99C4
 Haihao Xiang (haihao)         1F0C 31E8 B4FE F7A4 4DC1 DC99 E0F5 76D4 76FC 437F