Use latest nsync: allows running bazel after having downloaded for "make" build

The downloads directory for the make build is within the source tree seen by bazel,
which means that BUILD files (by whatever name) without those downloaded trees
must all be valid in their new location, or not recognized by bazel as being BUILD files.
The new version of nsync handles that, and this change pulls in that new version.

PiperOrigin-RevId: 174652898