Bump aiohttp from 3.11.18 to 3.12.15 in /demos/moderator_bot (#1585)

---
updated-dependencies:
- dependency-name: aiohttp
  dependency-version: 3.12.15
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

demos/moderator_bot/requirements-dev.txt

@@ -1,5 +1,5 @@
 -i https://pypi.org/simple/
-aiohttp==3.11.18
+aiohttp==3.12.15
 async-timeout==5.0.1
 atomicwrites==1.4.1
 attrs==25.3.0