Add sorbet dependencies

[JamieMagee]

Part of #7782 and step 1 of the adopting Sorbet in an existing codebase guide.

This will be followed with step 2 initializing sorbet

[Nishnha]

Hmm not sure what the difference between adding these gems here versus https://github.com/dependabot/dependabot-core/blob/main/common/dependabot-common.gemspec is.

[JamieMagee]

Yeah, I was torn too. But given the VSCode integration gems are installed here, it seemed like the more appropriate place for the Sorbet gems as well.

[Nishnha]

Well the omnibus uses the common gemspec so I guess it doesn't really matter where we install them as long as these tools are accessible from a bin/docker-dev-shell container

[mctofu]

Hmm not sure what the difference between adding these gems here versus https://github.com/dependabot/dependabot-core/blob/main/common/dependabot-common.gemspec is.

If we will need it to be available when running/testing the individual ecosystem gems it should go in dependabot-common.

[JamieMagee]

Yes, they'll be needed to power both IDE integrations, as well as in individual ecosystems. I'll move them to common.

[Nishnha]

Hmm maybe it's me but that didn't work. Did I run it right?

This was for when it was installed into omnibus. I'll check again once it's in common

$ git checkout jamiemagee/add-sorbet
> branch 'jamiemagee/add-sorbet' set up to track 'jamie/jamiemagee/add-sorbet'.
> Switched to a new branch 'jamiemagee/add-sorbet'

$ script/build bundler
> [+] Building 42.0s (43/43) FINISHED

[dependabot-core-dev] ~ $ cd bundler
[dependabot-core-dev] ~/bundler $ bundle install
> Resolving dependencies...

[dependabot-core-dev] ~/bundler $ bundle exec sorbet
> bundler: command not found: sorbet
> Install missing gem executables with `bundle install`

[JamieMagee]

@Nishnha Sorbet is available using srb

$ bundle exec srb
No sorbet/ directory found. Maybe you want to run 'srb init'?

A type checker for Ruby

Usage:
  srb                                 Same as "srb t"
  srb (init | initialize)             Initializes the `sorbet` directory
  srb rbi [options]                   Manage the `sorbet` directory
  srb (t | tc | typecheck) [options]  Typechecks the code

Options:
  -h, --help     View help for this subcommand.
  --version      Show version.

For full help:
  https://sorbet.org