floss: Start Flos API major version from 0

Floss team decided to start the API version from 0 as the API is
still volatile. Future changes to Floss API will require updating
the minor version.

Bug: 300216447
Tag: #floss
Test: ./build.py --target test
Test: m -j
Change-Id: Ibccde275e6385cb5b4916f37f1a5961ee8459898