doc: simplify Homebrew installation instructions

[ybeapps]

Removed brew tap requirement as SourceGit is now available in the official Homebrew Cask repository. 🎉🎉🎉🎉🎉🎉🎉🎉🎉

@love-linger I think we can think to setup a web hook on your repo so whenever a release is maid - it will trigger the update to hombres immediately instead of 4 times a day
I can provide the simple workflow - but I need to pass you the secret token (that will allow you to trigger github action in my repo) somehow.

how can we do this?

this can do the job:

name: Notify Homebrew Tap

on:
  release:
    types: [published]

jobs:
  notify-homebrew:
    runs-on: ubuntu-latest
    steps:
      - name: Notify Homebrew tap
        env:
          TAG: ${{ github.event.release.tag_name }}
          HOMEBREW_TAP_REPO_TOKEN: ${{ secrets.HOMEBREW_TAP_REPO_TOKEN }}
        run: |
          echo "📢 Notifying Homebrew tap of new release $TAG..."
          curl -X POST \
            -H "Authorization: token $HOMEBREW_TAP_REPO_TOKEN" \
            -H "Accept: application/vnd.github.v3+json" \
            https://api.github.com/repos/ybeapps/homebrew-sourcegit/dispatches \
            -d "{\"event_type\":\"new-sourcegit-release\",\"client_payload\":{\"version\":\"$TAG\"}}"
          echo "✅ Homebrew tap notified successfully"