Fix CI execution conditions: pull request + push to main

[paulo-ferraz-oliveira]

Description

We're making sure pushing to the main branch, as well as pull requests, and workflow dispatches, trigger CI.

• I have performed a self-review of my changes
• I have read and understood the contributing guidelines

[paulo-ferraz-oliveira]

@elbrujohalcon, I'm adding you as reviewer, but if CI passes I'm merging: I'm just tweaking the conditions under which CI occurs (push is to the current repo. only). Edit: merging requires 1 approval, so I'll leave it to you. You can approve and merge, or simply approve (or even comment and reject).