doc: update working-with-native-branches information
doc: update working-with-native-branches information

cherry-picked from
  https://github.com/webrtc/webrtc-org/pull/242

BUG=webrtc:11266

No-try: true
Change-Id: I0fd725d3bd30805416fd8a54f3d7a772772715f0
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/197811
Reviewed-by: Mirko Bonadei <d2c43c210eae6feef04f53bae50885e8152edcca@webrtc.org>
Commit-Queue: Philipp Hancke <563b103f57dc2044b12822c2a7559aa15cb1c987@googlemail.com>
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#32842}

TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc