chore(docs): Update bootstrap4.md (#3683)
chore(docs): Update bootstrap4.md (#3683)

Just use the regular 4.0.0 release instead of the outdated beta.
valor-software/ngx-bootstrap,valor-software/ngx-bootstrap,valor-software/ngx-bootstrap,valor-software/ngx-bootstrap,valor-software/ng2-bootstrap,valor-software/ng2-bootstrap