Add manual release job
This MR closes Implement manual release job in CI (#36 - closed) by re-implementing release.sh
in Python (mainly to add features) and adding a new CI job to execute that script to create a tag. For MRs against master
this job is run with --dry-run
to test functionality etc, while on pipelines directly on that branch, it's a manual
job.
Edited by Duncan Macleod