Add language to README about branch naming
Add the following branch renaming language to the README for this repository.
## Contributing
If you're working on PR for this project, create a feature branch off of `main`.
This repository follows the [Samvera Community Code of Conduct](https://samvera.atlassian.net/wiki/spaces/samvera/pages/405212316/Code+of+Conduct) and [language recommendations](https://github.com/samvera/maintenance/blob/master/templates/CONTRIBUTING.md#language). Please ***do not*** create a branch called `master` for this repository or as part of your pull request; the branch will either need to be removed or renamed before it can be considered for inclusion in the code base and history of this repository.
Text for PR
Title
Adds information for branch naming conventions to contributing section of the README.
Description