README.md is outdated in regards to status of 4.x

[Frulfump]

Says it's Beta, and "when it's released..."

[mgol]

Thanks for the report. cc @timmywil

[Frulfump]

Added comments to the PR. Status of 4.x is still Beta and 3.x is still Active in that PR (and in main)

[timmywil]

Thanks, opened #5787