feat: add tengo to valid commands

[ii64]

Hello and thank you for your interest on submitting a PR to this repository!

First and foremost, I hope you have read the CONTRIBUTING.md file.
If not, you can find it here: https://github.com/teknologi-umum/bot/blob/master/CONTRIBUTING.md

I would let you know that if you submit a PR without opening up an issue first,
your PR might be very likely rejected by the maintainers.

If you think you can go ahead without opening up an issue, please explain changes about your PR
in as much detail as possible.

Here is a few checklist that act as a reminder for your PR:

• I've opened a Github issue beforehand
• I've explained my PR in as much detail as possible.
• I'm using the conventional commit for my commit messages, or at least my commit messages are meaningful and easy to understand.
• I've added test files for new features.

After everything's complete, you can delete this placeholder text. Again, thank you!

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (06893fe) 81.46% compared to head (f7ebd11) 81.46%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #220   +/-   ##
=======================================
  Coverage   81.46%   81.46%           
=======================================
  Files          26       26           
  Lines        1597     1597           
=======================================
  Hits         1301     1301           
  Misses        296      296           

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