Completion for pipenv broken

[IevgenSobko]

pipenv completion changed for some time and current bash-it completion works no more.
According to https://github.com/pypa/pipenv#shell-completion they changed way completion is generated.

Expected Behavior

pipenv completion to work

Current Behavior

on pipenv completion I see error --completion is not supported

Possible Solution

Currently, applied following in my local copy, and it works
In file completion/available/pipenv.completion.bash
replace
eval "$(pipenv --completion)"
with
eval "$(_PIPENV_COMPLETE=bash_source pipenv)"

Context

Just command autocompletion

Steps to Reproduce

1. Make sure you enabled pipenv completion.
2. Try to fire pipenv completion.