Update METADATA to link to upstream project am: 2e54c35cfe am: 68d5fa8757 am: 5c4eb6637b am: 514da7c0a9

Original change: https://android-review.googlesource.com/c/platform/external/libmpeg2/+/2475549

Change-Id: Ifed9c464f1931d7c24c3c749095a9692e161d8cc
Signed-off-by: Automerger Merge Worker <[email protected]>