fix: deprecation warning on Faraday

[ngouy]

warning:

WARNING: Faraday::Connection#basic_auth is deprecated; it will be removed in version 2.0.
While initializing your connection, use #request(:basic_auth, ...) instead.
See https://lostisland.github.io/faraday/middleware/authentication for more usage info.

• I acknowledge that all my contributions will be made under the project's license
• I have made a material change to the repo (functionality, testing, spelling, grammar)
• I have read the Contribution Guidelines and my PR follows them
• I have titled the PR appropriately
• I have updated my branch with the main branch
• I have added tests that prove my fix is effective or that my feature works
• I have added the necessary documentation about the functionality in the appropriate .md file
• I have added inline documentation to the code I modified

[JenniferMah]

Thanks for your contribution @ngouy!

[silikone]

Thanks to @ngouy for the contribution.

@JenniferMah - Can we please have an update to the dependency spec such that the gem now is no longer resisting Faraday 2.0 and above.

twilio-ruby.gemspec:
spec.add_dependency('faraday', '>= 0.9', '< 2.0')
could now read:
spec.add_dependency('faraday', '>= 0.9', '< 3.0')

/S