The installation instructions put the lsp plugin in the wrong directory
for the `packadd` command. This updates the readme to fix the
installation instructions.
Fixes #62
You can install this plugin directly from github using the following steps:
```
- $ mkdir -p $HOME/.vim/pack/downloads/opt/lsp
- $ cd $HOME/.vim/pack/downloads/opt/lsp
+ $ mkdir -p $HOME/.vim/pack/downloads/opt
+ $ cd $HOME/.vim/pack/downloads/opt
$ git clone https://github.com/yegappan/lsp
```