docs(general): Update README.md with `brew` release cadence

[davidjeddy]

Added information regarding the release cadence to brew for MacOS consumers. https://github.com/bridgecrewio/checkov/issues/3334

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] I have added tests that prove my feature, policy, or fix is effective and works
• [x] New and existing tests pass locally with my changes
• [x] Any dependent changes have been merged and published in downstream modules

[gruebel]

@tsmithv11 is the placement fine for you?