Lint our yaml files as part of the CI

[oxarbitrage]

In #8433 we merged an invalid yaml for dependabot and we didn't realized the error until it was merged to main.

A fix was don at #8494

We can use some yaml validator to avoid this, here a few options discussed:
https://stackoverflow.com/questions/71334373/is-there-a-way-i-can-validate-yaml-files-on-github

[mpguerra]

@upbqdn is this something that could be done easily?

[upbqdn]

I don't know how quick this would be. Maybe @gustavovalverde?