Fix applying zsh theme in dev container in VS Code

[Kavignon]

After working on allowing pulling the Zsh terminal configuration from the host and having a fallback

• Added support for host's ZSH terminal configuration #53

I was testing the container through the docker in the terminal through:

docker build --no-cache -t elixir-update -f .devcontainer/Dockerfile .
docker run -it --rm elixir-update

Testing that way was working as expected, but I didn't during that time ensure that when I'd push the updated container image resulting from the PR (https://github.com/Elixir-journey/elixir-kickoff/pkgs/container/elixir-kickoff/323023919?tag=latest)

After configuring the theme for the container manually (bug listed here) we get this kind of feedback from the container's terminal:

But when opening the development container (without using the cache to ensure there no unexpected behaviour), this is the UX in the terminal.

[Kavignon]

I've been working in the main branch without realizing it, but things are working as intended now.

00589b5e62ab2e34756d7ed2a1414d5de5a6b4dc...0ed24cc1f8f7f3e962576aaea4e33f13a8fc08f4

To validate the behavior other than visually, here's what we can do

Ignoring the problems of spelling observed by the editor, things are working well:

• We can confirm that the theme is being applied
• We have highlighted commands
• We can see that the terminal is suggesting a command based on a prior command that I ran

In this instance, all that's missing is that the dev container is building the image on the fly, which can take up to a minute to set up on a machine.

The update can come in a later stage with the updated pre-built image: https://github.com/Elixir-journey/elixir-kickoff/pkgs/container/elixir-kickoff/323043388?tag=latest