Bump alembic from 1.18.5 to 1.20.1 (#631)

Bumps [alembic](https://github.com/sqlalchemy/alembic) from 1.18.5 to 1.20.1.
- [Release notes](https://github.com/sqlalchemy/alembic/releases)
- [Changelog](https://github.com/sqlalchemy/alembic/blob/main/CHANGES)
- [Commits](https://github.com/sqlalchemy/alembic/commits)

---
updated-dependencies:
- dependency-name: alembic
  dependency-version: 1.20.0
  dependency-type: direct:production
  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]

requirements.in

@@ -1,4 +1,4 @@
-alembic~=1.18.4
+alembic~=1.20.1
 astroid~=3.3.9
 blinker~=1.4
 boto3==1.35.99

requirements.txt

@@ -1,6 +1,6 @@
 # This file was autogenerated by uv via the following command:
 #    uv pip compile requirements.in
-alembic==1.18.5
+alembic==1.20.1
     # via
     #   -r requirements.in
     #   flask-migrate