Adding Updating instructions.

[christianlask]

No description provided.

[starcraftman]

@Hiberno Hello, I'm going to have to decline the PR.

This has been raised before however (i.e. #367, #364), it is intentional that we don't manage vim-plug with vim-plug, a clear discussion was on issue #240.

We already have a similar tip in our faq. I don't think we've any interest in promoting the idea more than that.

[junegunn]

@starcraftman Thanks for the explanation

@Hiberno I think PlugUpdate | PlugUpgrade is the simplest and the most straightforward solution, thus updated the wiki page accordingly.

https://github.com/junegunn/vim-plug/wiki/faq#shouldnt-vim-plug-update-itself-on-plugupdate-like-vundle

[christianlask]

@starcraftman Oh. I should've researched better. Sorry for the noise.

@junegunn Thanks for the hint.