Bump alembic from 1.6.5 to 1.7.6

Bumps [alembic](https://alembic.sqlalchemy.org) from 1.6.5 to 1.7.6.

---
updated-dependencies:
- dependency-name: alembic
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

requirements.txt

@@ -1,6 +1,6 @@
 Flask_SQLAlchemy==2.5.1
 SQLAlchemy==1.4.31
-alembic==1.6.5
+alembic==1.7.6
 Flask_Login==0.5.0
 Flask_Testing==0.8.1
 Flask==2.0.2