feat: automatic release using release-please

[bugloper]

Automatic release using Google's release-please action and https://www.conventionalcommits.org/en/v1.0.0/ Provides automatic versioning and changelogs

Note: Will need to add RUBYGEMS_AUTH_TOKEN & GEM_HOST_API_KEY

[bugloper]

@drnic @obie Please review this PR and see if it's a good idea. I have implemented this in this gem: https://github.com/SELISEdigitalplatforms/gotenberg

[drnic]

I’ll have a look at this when I next look at cutting a release