Update sqlalchemy requirement in /server

Updates the requirements on [sqlalchemy](https://github.com/sqlalchemy/sqlalchemy) to permit the latest version.
- [Release notes](https://github.com/sqlalchemy/sqlalchemy/releases)
- [Changelog](https://github.com/sqlalchemy/sqlalchemy/blob/main/CHANGES.rst)
- [Commits](https://github.com/sqlalchemy/sqlalchemy/commits)

---
updated-dependencies:
- dependency-name: sqlalchemy
  dependency-version: 2.0.51
  dependency-type: direct:production
...

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

Author: dependabot[bot]

server/requirements.txt

@@ -1,5 +1,5 @@
 tornado==6.5.7
-sqlalchemy>=2.0.50,<2.1.0
+sqlalchemy>=2.0.51,<2.1.0
 python-dateutil==2.9.0.post0
 marshmallow-sqlalchemy>=1.5.0
 tornado-prometheus==0.1.2