Added bump-my-version config

Please test this before approving.

Steps to test

1. Install bump-my-version pip install bump-my-version
2. Test all release types (in no particular order)
   1. Bump to a minor version (2.8.2.0->2.9.0.0) bump-my-version bump minor
   2. Major (2.8.2.0->3.0.0.0) bump-my-version bump major
   3. Patch (2.8.2.0->2.8.3.0) bump-my-version bump patch
   4. Smallpatch (2.8.2.0->2.8.2.1) bump-my-version bump smallpatch
   5. Release candidate (2.8.2.1->2.8.2.1rc1) bump-my-version bump rc

NB: This tool requires either all or none of the versions it deals with to have a "smallpatch".