Update flask-migrate requirement from ~=2.7.0 to ~=3.1.0

Updates the requirements on [flask-migrate](https://github.com/miguelgrinberg/flask-migrate) to permit the latest version.
- [Release notes](https://github.com/miguelgrinberg/flask-migrate/releases)
- [Changelog](https://github.com/miguelgrinberg/Flask-Migrate/blob/main/CHANGES.md)
- [Commits](miguelgrinberg/Flask-Migrate@v2.7.0...v3.1.0)

---
updated-dependencies:
- dependency-name: flask-migrate
  dependency-type: direct:production
...

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

Author: dependabot[bot]

requirements.in

@@ -1,6 +1,6 @@
 Flask-Gzip==0.2
 Flask-Mail==0.9.1
-Flask-Migrate~=2.7.0
+Flask-Migrate~=3.1.0
 Flask-pyoidc~=3.7.0
 Flask~=1.1.4
 csh_ldap~=2.3.1

requirements.txt

@@ -50,7 +50,7 @@ flask-gzip==0.2
     # via -r requirements.in
 flask-mail==0.9.1
     # via -r requirements.in
-flask-migrate==2.7.0
+flask-migrate==3.1.0
     # via -r requirements.in
 flask-pyoidc==3.7.0
     # via -r requirements.in
@@ -60,6 +60,8 @@ flask-sqlalchemy==2.5.1
     #   flask-migrate
 future==0.18.2
     # via pyjwkest
+greenlet==1.1.2
+    # via sqlalchemy
 gunicorn==20.0.4
     # via -r requirements.in
 idna==3.3
@@ -176,8 +178,6 @@ wheel==0.37.1
     # via pip-tools
 wrapt==1.12.1
     # via astroid
-zipp==3.8.0
-    # via importlib-resources
 
 # The following packages are considered to be unsafe in a requirements file:
 # pip