build(deps): bump pgvector from 0.4.0 to 0.4.1 in /backend

Bumps [pgvector](https://github.com/pgvector/pgvector-python) from 0.4.0 to 0.4.1.
- [Changelog](https://github.com/pgvector/pgvector-python/blob/master/CHANGELOG.md)
- [Commits](https://github.com/pgvector/pgvector-python/compare/v0.4.0...v0.4.1)

---
updated-dependencies:
- dependency-name: pgvector
  dependency-version: 0.4.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

backend/requirements.txt

@@ -21,7 +21,7 @@ alembic==1.14.0
 peewee==3.18.1
 peewee-migrate==1.12.2
 psycopg2-binary==2.9.9
-pgvector==0.4.0
+pgvector==0.4.1
 PyMySQL==1.1.1
 bcrypt==4.3.0