Update trusted providers of github actions

[liranr23]

Based on https://github.com/instructlab/dev-docs/blob/main/docs/github-actions-use-policy.md#trusted-providers-of-github-actions, update the trusted providers of instructlab.

Related to https://github.com/instructlab/instructlab/issues/1218

[liranr23]

@leseb I can't tell on which Misspelled words the spellcheck fails. i guess it's the shellcheck. do you wish me to add it to the dictionary?

[leseb]

@leseb I can't tell on which Misspelled words the spellcheck fails. i guess it's the shellcheck. do you wish me to add it to the dictionary?

Yes it is:

Misspelled words:
<context> docs/github-actions-providers.md
--------------------------------------------------------------------------------
Shellcheck

Please add it to .spellcheck-en-custom.txt and run make spellcheck-sort. Thanks!