New GitHub Actions CI: github.event_name instead of github.event
New GitHub Actions CI: github.event_name instead of github.event

Fixes error where a new image was not being built and pushed to Docker Hub after merge to dev (or release).

ewels/NGI-RNAseq,ewels/NGI-RNAseq,ewels/NGI-RNAseq,ewels/NGI-RNAseq,ewels/NGI-RNAseq