Upgrade dart_sass to fix CI build

[Nihisil]

Issue

The template can't be build on CI anymore: https://github.com/nimblehq/elixir-templates/actions/runs/5408543870/jobs/9827719749

With error:

* (RuntimeError) Installing dart_sass on Linux platforms requires version >= 1.58.0, got: "1.49.11"
    (dart_sass 0.7.0) lib/dart_sass.ex:218: DartSass.install/0
    (dart_sass 0.7.0) lib/dart_sass.ex:204: DartSass.install_and_run/2
    (dart_sass 0.7.0) lib/mix/tasks/sass.ex:53: Mix.Tasks.Sass.install_and_run/1
    (mix 1.14.3) lib/mix/task.ex:421: anonymous fn/3 in Mix.Task.run_task/4
    (mix 1.14.3) lib/mix/task.ex:479: Mix.Task.run_alias/6
    (mix 1.14.3) lib/mix/cli.ex:84: Mix.CLI.run_task/2

Expected

CI is green.

Steps to reproduce

1. Trigger CI build
2. CI will be red