chore: update readme

[wolfv]

Multiple people have notified me that the README still reads "alpha" which is definitely not true. Pixi is used in production by a lot of organizations these days and we are working very hard to not introduce breaking changes in the file format.

[nichmor]

if we are on this page, maybe we could add links or logos about what projects are using pixi ? or where we are mentioned?

[tdejager]

if we are on this page, maybe we could add links or logos about what projects are using pixi ? or where we are mentioned?

We do have a docs page about it.

[nichmor]

if we are on this page, maybe we could add links or logos about what projects are using pixi ? or where we are mentioned?

We do have a docs page about it.

yes but it's only in community sub-page, I think having some logos of companies at the end of readme.md like rerun would be nice

[tdejager]

if we are on this page, maybe we could add links or logos about what projects are using pixi ? or where we are mentioned?

We do have a docs page about it.

yes but it's only in community sub-page, I think having some logos of companies at the end of readme.md like rerun would be nice

Sure but I feel its out of scope for this PR :)