chore: use the centralized release scripts from the toys repository

[dazuma]

The copy of the release scripts currently in the repo is slightly out of date. The most up to date scripts are in the toys repository. This change removes the copy here and references the central scripts. (I'll do the same in the contrib repo.) This will pick up minor fixes that have been made to the central scripts in the past year or two, and let me make additional changes in one place and have them apply to both repositories.

Ref: open-telemetry/opentelemetry-ruby-contrib#508

[arielvalentin]

In retrospect I should have asked the question, are you planning on adding the release scripts to the toys gem itself so you are not cloning the repo?

[dazuma]

@arielvalentin No, they're not conceptually part of the toys gem (any more than someone's gem-releasing rake tasks would be part of the core rake gem). Conceivably they could be packaged in a different gem, but I haven't looked into that.

[dazuma]

@arielvalentin Is this okay for now? Generally, this is the way I've been handling these release scripts in the repos that use them. (e.g. here's the script for the CloudEvents Ruby SDK: https://github.com/cloudevents/sdk-ruby/blob/main/.toys/.toys.rb#L22)