gamesdk: add repohooks

Add repohooks to prevent breaking Swappy ABI without updating
the minor/major version macros.

The script simply checks if one of the public headers of swappy changed
and errors if the minor/major version macros were not updated together
with the change.

Test: manual
Change-Id: I3ebdc2c4f785f1e94162333af0ac454396854f81
2 files changed