Update README.md

[liamdempsey]

Corrected the spelling of 'after'.

[salcode]

@liamdempsey great to get your pull request (PR) and on a regular project it would be great to merge. Because this is a practice repo, I do have some particular requirements that are generally considered good form and helpful to the repo maintainer.

You can see the contributing information at https://github.com/salcode/gitpractice/blob/master/CONTRIBUTING.md

This is all included in the contributing doc but here is a quick list about this specific PR.

1. Please Open An Issue for this fix (See more info)
2. Please use a multiple line commit message with a final ine of "Fix #99", where 99 is replaced with the number of the issue you opened in the first step. (See more info)
3. Please create a new branch for your PR (e.g. fix-mispell-after)
4. Please make your PR from your new branch against the develop branch
   

Note: In my experience, the easiest way to make these changes is to close this PR and create a new one.