Fix macOS runners - add netcdf-cxx and netcdf-fortran package to brew install

[mattw-nws]

Add netcdf-cxx and netcdf-fortran package to brew install... looks like these were broken out into their own formulae about 15 days ago.

Additions

• netcdf-cxx and netcdf-fortran brew install command for macOS build action
• updates to similar brew install command in .gitpod.Dockerfile

Removals

Changes

Testing

Screenshots

Notes

Todos

Checklist

• PR has an informative and human-readable title
• Changes are limited to a single goal (no scope creep)
• Code can be automatically merged (no conflicts)
• Code follows project standards (link if applicable)
• Passes all existing automated tests
• Any change in functionality is tested
• New functions are documented (with a description, list of inputs, and expected output)
• Placeholder code is flagged / future todos are captured in comments
• Project documentation has been updated (including the "Unreleased" section of the CHANGELOG)
• Reviewers requested with the Reviewers tool ➡️

Testing checklist (automated report can be put here)

Target Environment support

• Linux
• macOS