Add --camera-facing

Add an option to select the camera by its lens facing (front, back or
external).

PR #4213 <https://github.com/Genymobile/scrcpy/pull/4213>

Co-authored-by: Romain Vimont <rom@rom1v.com>
Signed-off-by: Romain Vimont <rom@rom1v.com>

app/data/bash-completion/scrcpy

@@ -11,6 +11,7 @@ _scrcpy() {
         --audio-output-buffer=
         -b --video-bit-rate=
         --camera-id=
+        --camera-facing=
         --camera-size=
         --crop=
         -d --select-usb
@@ -104,6 +105,10 @@ _scrcpy() {
             COMPREPLY=($(compgen -W 'output mic' -- "$cur"))
             return
             ;;
+        --camera-facing)
+            COMPREPLY=($(compgen -W 'front back external' -- "$cur"))
+            return
+            ;;
         --lock-video-orientation)
             COMPREPLY=($(compgen -W 'unlocked initial 0 1 2 3' -- "$cur"))
             return