fix(brew): move away from deprecated definitions

[ember-ana]

Description

I've been getting the following deprecation warnings when using homebrew:

Warning: Calling the `verified` parameter in the `url` stanza is deprecated! Use the default URL verification behaviour instead.
Please report this issue to the sableclient/homebrew-sable tap (not Homebrew/* repositories), or even better, submit a PR to fix it:
  /opt/homebrew/Library/Taps/sableclient/homebrew-sable/Casks/sable.rb:6

Warning: Calling `postflight` is deprecated! Use `postflight_steps` instead.
Please report this issue to the sableclient/homebrew-sable tap (not Homebrew/* repositories), or even better, submit a PR to fix it:
  /opt/homebrew/Library/Taps/sableclient/homebrew-sable/Casks/sable.rb:25

This resolves those warnings by updating the involved stanzas to their new versions.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas (N/A)
• I have made corresponding changes to the documentation (N/A)
• My changes generate no new warnings

AI disclosure:

• Created without the usage of AI
• Partially AI assisted (clarify which code was AI assisted and briefly explain what it does).
• Fully AI generated (explain what all the generated code does in moderate detail).

Signed-off-by: ember ana mint.git@thei.rs