Fix warning due to Elixir 1.17

[dinhhuydh]

Overview

As discussion in #44 that the library needs new implementation because at the run-time, it does not know the font is module or struct, so it raises warning when calling font.name. This is fix for warning due to Elixir 1.17 for current implementation.

[cgrothaus]

@andrewtimberlake Does this approach fix the problem in a correct way?

[dinhhuydh]

Closed as the issue fixed in #52.