Bump idna from 3.4 to 3.7

Bumps [idna](https://github.com/kjd/idna) from 3.4 to 3.7.
- [Release notes](https://github.com/kjd/idna/releases)
- [Changelog](https://github.com/kjd/idna/blob/master/HISTORY.rst)
- [Commits](kjd/idna@v3.4...v3.7)

---
updated-dependencies:
- dependency-name: idna
  dependency-type: direct:production
...

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

requirements.txt

@@ -20,7 +20,7 @@ Flask-Mail==0.9.1
 Flask-Migrate==4.0.4
 Flask-SQLAlchemy==3.0.5
 Flask-WTF==1.1.1
-idna==3.4
+idna==3.7
 itsdangerous==2.1.2
 Jinja2==3.1.2
 joblib==1.3.1