Update readme following security changes + bump dependencies

[litil]

Description

Changes related to security policy were introduced lately. Now, to be able to use Aircall Everywhere, you need to reach out to Aircall's support team, so that they add your domain to our whitelist.

This PR modifies the readme file, the demo page and bump dependencies. It also migrated from CircleCI to Github actions.

Submission

• [x] Your branch is based on master
• [x] Your code is unit tested
• [x] Github actions are green (coverage and lint)
• [x] Add team "CTI" as "Reviewer" for the PR
• [x] Name your PR with the convention fix|feat|impr(<subject>): description.

[litil]

The code coverage of this PR is 99.25% :white_check_mark: Coverage for master is %.

[litil]

The code coverage of this PR is 99.25% :white_check_mark: Coverage for master is %.

[litil]

The code coverage of this PR is 99.25% :white_check_mark: Coverage for master is %.