[gi-docgen] Created tag 2021.5

[Emmanuele Bassi <ebassi src gnome org>]

The signed tag '2021.5' was created.

Tagger: Emmanuele Bassi <ebassi gnome org>
Date: 1618499558 +0100

    gi-docgen 2021.5

Changes since the last tag '2021.4':

Emmanuele Bassi (5):
      Add missing licensing terms for the manifest
      Add pyproject.toml to the manifest
      Merge branch 'wip/smcv/more-in-sdist' into 'main'
      Merge branch 'wip/smcv/turn-off-dev-tests' into 'main'
      Release gi-docgen 2021.5

Simon McVittie (2):
      build: Add an option to turn off development tests
      build: Include more files in setuptools sdist