Fix CI and Multiple main -> master changes

[emiliocuestaf]

Description

Multiple workflows along with the README were using the old naming convention for the principal branch, this PR fixes that.

Contributor Checklist

• Commit messages follow the project guidelines.
• [N/A] Tests that thoroughly check the new feature have been added/Regression tests checking the bug and its fix have been added; the added tests pass locally
• [N/A] Changes are API compatible.
• [N/A] Applicable backports have been included in the description.

Reviewer Checklist

• The PR has a milestone assigned.
• The title and description correctly express the PR's purpose.
• Check contributor checklist is correct.
• Check CI results: changes do not issue any warning.
• Check CI results: failing tests are unrelated with the changes.

[raulojeda22]

LGTM