chore: correct image names in Tilt config file

[jeronimoalbi]

Follow-up to #377

This fixes an issue with Tilt failing because of Docker image names.
It seems to work fine when using "-" instead of "_" for the image names.

The change in the names triggers a Docker warning for any of these two names, for example:

Image not used in any Docker Compose config:
    ✕ ditherchat-reader-main
Did you mean…
    - ditherchat_reader-main
    - ditherchat_api-main
    - postgres
Skipping this image build
If this is deliberate, suppress this warning with: update_settings(suppress_unused_image_warnings=["ditherchat-reader-main"])
Successfully loaded Tiltfile (265.501334ms)

So I added the recommended call to Tilt's update_settings() to ignore them.

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[jeronimoalbi]

@mazzy89 can you take a look 🙏?

[mazzy89]

Thank you @jeronimoalbi. I've provided a clearner PR though that tshould help to fix the problem in a leaner way and actually it is the recommended way by Tilt. Please see #379