Error while installing via vim plug

**Describe the bug**
I am getting Error when I try to install markdown-preview plugin for neovim v0.7.0

**To Reproduce**
used this to install the plug using vim plugin
```sh
Plug 'iamcco/markdown-preview.nvim', { 'do': { -> mkdp#util#install() }, 'for': ['markdown', 'vim-plug']}
```

**Desktop (please complete the following information):**
- OS: MacOS Big Sur 11.6

Log:

```
x Post-update hook for markdown-preview.nvim ... Vim(call):E117: Unknown function: mkdp#util#install
```