Release 6.0.4

Release 6.0.3

[Librarian] Version Bump

Release 6.0.1

Version Bump v6.0.0: Remove sinatra dependency + features and fixes

Version Bump v5.3.0: Dynamic Template support

Version Bump v5.2.0: PR sendgrid#234: Helpers for email statistics - …

…global, category, subuser

Version Bump v5.1.0: sendgrid#173: Update ruby-http-client dependency

Version Bump v5.0.0: BREAKING CHANGE - see CHANGELOG

Version Bump: 4.3.3: sendgrid#157: Specify required ruby version as '…

…>= 2.2'