README: confusing/misleading description of covenant as "first" code of conduct

[Chealer]

The README.md's introduction reads:

The first and most popular code of conduct for open and ethical source communities.

First, this is unclear, as "ethical source" is a rare term, mostly associated with sourcing.

Secondly, "first" is confusing in that sentence. It is unclear which dimension it refers to. If it means "oldest", does it mean this CoC is the oldest one which was written targeting not just open source communities, but also "ethical source" communities? As things stand, readers are likely to interpret this as meaning that this CoC predates Ubuntu's (from 2004 or 2005) and others.