chore(deps): Update asyncpg requirement in /demo (#3971)

Updates the requirements on [asyncpg](https://github.com/MagicStack/asyncpg) to permit the latest version.
- [Release notes](https://github.com/MagicStack/asyncpg/releases)
- [Commits](MagicStack/asyncpg@v0.30.0...v0.31.0)

---
updated-dependencies:
- dependency-name: asyncpg
  dependency-version: 0.31.0
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: jamshale <31809382+jamshale@users.noreply.github.com>

Author: dependabot[bot]