Add a list of GnuPG fingerprints.

This is not as good as personal keysigning (ala debian) but better than
nothing.

Originally committed as revision 16377 to svn://svn.ffmpeg.org/ffmpeg/trunk

MAINTAINERS

@@ -306,3 +306,9 @@ Windows Cygwin                          Victor Paesa
 ADI/Blackfin DSP                        Marc Hoffman
 Sparc                                   Roman Shaposhnik
 x86                                     Michael Niedermayer
+
+
+GnuPG Fingerprints of maintainers
+=================================
+
+Michael Niedermayer             9FF2128B147EF6730BADF133611EC787040B0FAB