Release v3.0.0 - 2024-10-29

Tag release v3.0.0

References: #36, #37, #38

• Feature - Uses rack ~> 3 as the minimum.

• Feature - Drop support for Ruby 2.5 and 2.6.

• Feature - Support additional configuration options through ENV.

• Feature - Moves error classes into the Errors module.

• Issue - Set RackMiddleware's #find_session, #write_session, and #delete_session as public.

• Issue - Validate Configuration has a secret key on RackMiddleware#initialize instead of on #find_session.