Bump idna from 3.7 to 3.8 (#336)

Bumps [idna](https://github.com/kjd/idna) from 3.7 to 3.8.
- [Release notes](https://github.com/kjd/idna/releases)
- [Changelog](https://github.com/kjd/idna/blob/master/HISTORY.rst)
- [Commits](kjd/idna@v3.7...v3.8)

---
updated-dependencies:
- dependency-name: idna
  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>

requirements.txt

@@ -12,7 +12,7 @@ Flask-Login==0.6.3
 Flask-Session==0.8.0
 Flask-SQLAlchemy==3.1.1
 Flask-WTF==1.2.1
-idna==3.7
+idna==3.8
 itsdangerous==2.2.0
 Jinja2==3.1.4
 Mako==1.3.5