remove references to v7 beta CLI
remove references to v7 beta CLI

[#172111892]

Co-authored-by: Belinda Liu <496afffef642eb3807bf00ef2898c80e8c6b937c@pivotal.io>
Co-authored-by: Weyman Fung <4ab5e17be5c5cdce6cf54d6174afda06421ccec1@pivotal.io>

cloudfoundry/docs-dev-guide