Problem:

After merging PR which closes an issue and tagging this with git tag issue lands in "Upcoming" section of changelog and PR is in tagged one.

Steps taken:

1. Create issue (example)
2. Create PR and link it to issue with github keyword like related (example)
3. Merge PR (example)
4. Tag it with git tag (example)
5. Generate changelog (example)

Expected:

Closed issue described in tagged section, not in "Upcoming".

Other info

Tagging and releasing is managed by this script and this line does actual changelog generation.

Version used: 1.14.3, also tested on master (3ed2fae)

This might be related to #560