README: replace outdated xinerama reference with xpresent

200992f stopped linking mpv to
libXinerama so this library isn't needed anymore. However, we do use
xpresent so mention that instead since all the other needed xorg
libraries are listed as well.

Author: Dudemanguy

README.md

@@ -90,7 +90,7 @@ Example:
 Essential dependencies (incomplete list):
 
 - gcc or clang
-- X development headers (xlib, xrandr, xext, xscrnsaver, xinerama, libvdpau,
+- X development headers (xlib, xrandr, xext, xscrnsaver, xpresent, libvdpau,
   libGL, GLX, EGL, xv, ...)
 - Audio output development headers (libasound/ALSA, pulseaudio)
 - FFmpeg libraries (libavutil libavcodec libavformat libswscale libavfilter