Update notify_paths for Macports binary support

[joergschultzelutter]

• added path /opt/local/bin in order to support installations via Macports

Description:

Related issue (if applicable): n/a

This minor change adds Macports' default path to the plugin's list of paths where the terminal-notifier gets located.

Checklist

• [x] The code change is tested and works locally.
• [x] There is no commented out code in this PR.
• [x] No lint errors (use flake8)
• [x] 100% test coverage

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (3cd5895) 99.27% compared to head (ac4826c) 99.27%.

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1052 +/- ## ======================================= Coverage 99.27% 99.27% ======================================= Files 135 135 Lines 17600 17600 Branches 3592 3592 ======================================= Hits 17472 17472 Misses 119 119 Partials 9 9 ```

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[caronc]

Thank you!🙏🙏