Exclude `examples/` directory from the shipped gem

[connorshea]

Checklist

• I have looked into the Readme and Examples, and have not found a suitable solution or answer.
• I have looked into the API documentation and have not found a suitable solution or answer.
• I have searched the issues and have not found a suitable solution or answer.
• I have searched the Auth0 Community forums and have not found a suitable solution or answer.
• I agree to the terms within the Auth0 Code of Conduct.

Describe the problem you'd like to have solved

Right now the gem ships with the examples/ directory, which adds extra, unnecessary size on every install and - for some users - noise in vulnerability detection tools.

Describe the ideal solution

Exclude the examples/ directory from the gem files in the gemspec.

Alternatives and current workarounds

No response

Additional context

No response