📄 Update README

[kaylahrose]

Is there an existing request for this change?

• [X] I have searched the existing issues

Context for documentation change

1. Human Essentials has switched to date-based versioning. The README currently has directions on the old versioning style.
2. Send Update Email to Human Essential Users has some information that is out of date as well (source)

Proposed solution

1. Update the Deployment Process > Tag & Release section to provide instructions on date-based versioning.
2. Correct email update section

Resources that can help

Date-Based Versioning source Email Update source

Collaborators

@awwaiid

Code of Conduct

• [X] I've read the Code of Conduct and understand my responsibilities as a member of the Ruby for Good community