Typo Update pr-guidelines.md

[defitricks]

Description:

This PR fixes a typo in the merge requirements section of the PR guidelines. Specifically, the phrase "CI must passing" has been corrected to "CI must pass".

Issue:

• The original phrase "CI must passing" is incorrect because after the modal verb "must", the main verb should be used in its base form (i.e., "pass"). "Passing" is a present participle, which does not fit grammatically in this context.

Importance:

• Correcting this typo is important for clarity and accuracy. Using the correct grammatical structure ensures that the guidelines are clear and understandable for all contributors. Additionally, it helps maintain the professional quality of the documentation.

Please review and approve the change.

[smartcontracts]

/ci authorize 952286a

[smartcontracts]

Thanks!