Grant contributer access

[jnross]

@georgik @igrr: Would you grant contributor access to some folks on our team? We don't need to be able to push or even merge to main, but we would like be able to create and push branches and and create PRs without using an external fork.

Here are the github IDs to add:
@jnross
@rgcottrell
@mykmelez
@Chondrules
@kevin-june

[igrr]

Have done, you should receive invitations.