Add missing option libaribcaption

References
----------
[1] https://git.videolan.org/?p=ffmpeg.git;a=commit;h=b6138633cdf2ecae22c4c02029e91245c430c4fe

.SRCINFO

@@ -1,7 +1,7 @@
 pkgbase = ffmpeg-full
 	pkgdesc = Complete solution to record, convert and stream audio and video (all possible features including libfdk-aac)
 	pkgver = 6.1
-	pkgrel = 2
+	pkgrel = 3
 	url = https://www.ffmpeg.org/
 	arch = x86_64
 	license = custom: nonfree and unredistributable
@@ -15,6 +15,7 @@ pkgbase = ffmpeg-full
 	depends = alsa-lib
 	depends = aom
 	depends = aribb24
+	depends = libaribcaption
 	depends = avisynthplus
 	depends = bzip2
 	depends = cairo