Add fontconfig to the list of installed packages

[bugbounce]

Summary

Adds fontconfig to the list of installed packages.

Use Cases

We are running into font issues for our web applications when using this stack.

Checklist

• I have viewed, signed, and submitted the Contributor License Agreement.
• I have linked issue(s) that this PR should close using keywords or the Github UI (See docs)
• I have added an integration test, if necessary.
• I have reviewed the styleguide for guidance on my code quality.
• I'm happy with the commit history on this PR (I have rebased/squashed as needed).

[pacostas]

Do you have an example of the font issues you have, or instructions on how to reproduce it?

[sophiewigmore]

Hey @bugbounce can you discuss a bit more about your use case for needing this package during both build and runtime?

We usually take a conservative approach to adding new packages to the stack images in order to limit vulnerability surface area, so I'd really like to understand fully what the benefit will be here.

[bugbounce]

Apologies for the delayed response. Thanks for clarifying the condition for including new packages. Our web app includes custom fonts and also relies on font substitution for loading external Map frames. Without the fontconfig package, we were ending with empty frames. I don't really have a small example to reproduce the issue. I can get more information from my application team if required.
Thanks for your time.