PRs targeting dev branch (e.g. gandalf/docs-namespace-cleanup → dev)
were not triggering CI because the workflow on: filters only listed
main. This change adds 'dev' to both push and pull_request branch
filters on CI, and to the pull_request trigger on dual-approval.
Fixes PRI-526.
Co-Authored-By: Paperclip <noreply@paperclip.ing>