feat: Add Go Modules and add Go 1.19 compatibility#112

AlaricWhitney wants to merge 2 commits intosendgrid:mainsendgrid/rest:mainfrom

AlaricWhitney:Add-Go-Modules-and-add-go-1.19-compatibilityAlaricWhitney/rest:Add-Go-Modules-and-add-go-1.19-compatibilityCopy head branch name to clipboard