Added deprecation message in readme

[maxmil7]

Added deprecation message in readme so the new versions of murmurhash3js can be published from the original repo:

Here is a list of tasks needed to move over the repository

• [ ] Publish v3.2.0 of murmurhash3js based on code code in this repo: https://github.com/karanlyons/murmurHash3.js
• [ ] Add deprecated message in description of this repo and make it readonly
• [ ] Merge this PR

[maxmil7]

@karanlyons @pid Thank you for your work in creating the module and maintaining the package for it. It would be great to make the transition to the original module based on comments in #4

I have tried to outline the tasks in the readme. @karanlyons can you please help with the first task

Once the new version is published, I believe we can merge this PR and mark the repo as read only. Please let me know if there is anything I can do to help with the transition. Thanks again for both of your work

[ricardobeat]

@karanlyons any chance you'll get around to publishing the updated package?